26340415
Effects of Filtering Policies on Task Performance in a Desktop CVE System
To quantify the regularity of state updates, the concept of Irregular Degree was introduced. Two experiments corresponding to four different filtering policies were designed. In the first experiment three filtering policies based on Irregular Degree were compared. In the second experiment, the filtering policy achieving the best task performance in the first experiment was selected to compare with other filtering policies. The results of the first experiment indicate that the stability of state updates per second is a more important impact factor than Irregular Degree on the task performance. The results of the second experiment indicate that corresponding to different state updates per second, the filtering policies can achieve different task performance.
41643555
A Fuzzy Dead Reckoning Algorithm for Distributed Interactive Applications
A fuzzy Dead Reckoning (DR) algorithm for distributed interactive applications is proposed in this paper. Since fixed threshold cannot adequately handle the dynamic relationships between moving entities, some multi-level threshold DR algorithms were proposed in the past few years. In these algorithms the level of threshold is adaptively adjusted based on the distance between entities. The proposed fuzzy DR algorithm is based on multi-level threshold DR algorithm and takes all properties of entity (e.g. position, size and view angle etc.) into consideration when adjusting the level of threshold. This algorithm employs fuzzy correlation degree to measure the relationships between entities and determine the level of threshold for DR algorithm. Fuzzy consistent relation is used to distribute weight for each property. Simulation results indicate that fuzzy DR algorithm can achieve a considerable reduction in the number of state update messages while maintaining adequate accuracy in extrapolation.
17619661
Your way your missions: from location-based to route-based pervasive gaming
In this paper, we describe the design and implementation of a route-based pervasive game named Your Way Your Missions (YWYM). Since the game obtains the planned routes of players and returns missions in the routes, players can play the game in a casual way, without changing their routes to respond to picked up missions. A self-reporting method is proposed to obtain the planned routes of players, and a corresponding route defining tool is developed upon Google Maps. Two approaches to realize route-based mission adaptation with spatial databases are presented.
11794423
An adaptive consistency maintenance approach for replicated continuous applications
Consistency maintenance is a key problem to replicated continuous applications and dead reckoning (DR) algorithm is widely used in this area. In order to eliminate short-term inconsistency caused by DR algorithm, local-lag approach was proposed. For the purpose of simplicity, fixed lag value is used by local-lag approach and the performance of the approach is greatly deteriorated. In this paper, an adaptive consistency maintenance approach, which is based on local-lag approach, is proposed. The new approach can adjust lag value according to the estimated typical network latency. In order to ensure the criterion of consistency correctness, a lag value adjustment method is also proposed. Through two experiments, the performance of the new approach is evaluated and the results indicate that it is feasible and can greatly improve the performance of the application.
40616325
A Color Bar Based Affective Annotation Method for Media Player
Multimedia technology has been developing quickly since the computer was invented. Nowadays, more and more people use media players to watch movies and TV shows on their computer. But it seems that we are too busy sometimes to spare nearly two hours watching a movie from beginning to end. We’d like to find and watch the most exciting episodes that we are interested in as soon as possible. The media players we use often only provide a slider bar for locating, which is rather low in efficiency. Respecting this, an affective annotation method for video clips is proposed in this paper and the method is implemented in an affectively annotated media player. In addition, two experiments were set up to evaluate the proposed method. Experiment results indicate that affective annotation facilitates the subjects in quick locating target events and helps them understand the scenarios better.
14850996
Effects of network characteristics on task performance in a desktop CVE system
The influences of network characteristics on the task performance in a desktop collaborative virtual environment (CVE) system were studied. In the experiment, two participants worked together to accomplish a collaborative task and a network emulator was utilized to simulate real network characteristics. The task used in the experiment was designed to be highly interactive and had rigid requirements on network characteristics (e.g. latency and packet loss). The objective performance and subjective assessment were recorded and analyzed quantitatively as a function of network latency and packet loss rate. The experiment results show that network latency has no distinct effect on task performance when network latency is less than 200 ms and lightly affect task performance when network latency is between 200 and 600 ms; packet loss has no effect on task performance when there are 40 state update messages received per second and lightly affect task performance when there are between 15 and 40 state update messages received per second.
18273444
A system of 3D hair style synthesis based on the wisp model
Hair plays an important role in the image of the human face. However, it is still difficult and time consuming to synthesize realistic 3D CG hair images. In this paper, we present an integrated system for 3D computer graphics (CG) hair image synthesis based on a trigonal prism wisp model. By applying the trigonal prism wisp model, 2D hair distribution maps and other CG techniques to our system, we can successfully and efficiently synthesize realistic CG hair style images. A 3D hair style editing tool (HET) is incorporated into the system to support the creation of 3D hair styles. We have also integrated this system with other research results to construct a system for 3D CG character synthesis.
441449
A novel ant clustering algorithm based on cellular automata
Based on the principle of cellular automata in artificial life, an artificial ant sleeping model (ASM) and an ant algorithm for cluster analysis (A4C) are presented. Inspired by the behaviors of gregarious ant colonies, we use the ant agent to represent a data object. In ASM, each ant has two states: a sleeping state and an active state. The ant's state is controlled by a function of the ant's fitness to the environment it locates and a probability for the ants becoming active. The state of an ant is determined only by its local information. By moving dynamically, the ants form different subgroups adaptively, and hence the data objects they represent are clustered. Experimental results show that the A4C algorithm on ASM is significantly better than other clustering methods in terms of both speed and quality. It is adaptive, robust and efficient, achieving high autonomy, simplicity and efficiency.
8213932
End-to-End Asymmetric Link Capacity Estimation
Knowledge of link capacity is important for network design, management, and utilization. With the increasing popularity of asymmetric link technologies (such as DSL, 1xRTT, and satellite links), it is desirable to have a capacity estimation technique, which can simultaneously measure forward and backward direction link capacities on an Internet path. Moreover, this estimation must often be “sender only”, because of receiver limitations or lack of standards. In this study, we propose a simple, fast and accurate technique, called AsymProbe, to estimate asymmetric link capacities. AsymProbe is a “sender only”, round trip procedure. It achieves asymmetric link capacity estimation by strategically altering the ratio of probe and acknowledgement packet sizes. Using simulation and testbed experiments, we validate AsymProbe with a variety of network configurations. The results show that AsymProbe can correctly estimate the asymmetric link capacities as long as an appropriate packet size ratio can be employed.
43431226
Wavelet-based optical flow estimation
A new algorithm for accurate optical flow (OF) estimation using discrete wavelet approximation is proposed. The computation of OF depends on minimizing the image and smoothness constraints. The proposed method takes advantages of the nature of wavelet theory, which can efficiently and accurately approximate any function. OF vectors and image functions are represented by means of linear combinations of scaling basis functions. Based on such wavelet-based approximation, the leading coefficients of these basis functions carry global information about the approximated functions. The proposed method can successfully convert the problem of minimizing a constraint function into that of solving a linear system of a quadratic and convex function of scaling coefficients. Once all the corresponding coefficients are determined, the flow vectors can be obtained accordingly. Experiments have been conducted on both synthetic and real image sequences. In terms of accuracy, the results show that our approach outperforms the existing methods which adopted the same objective function as ours.
2673173
State Aware Data Dissemination over Structured Overlays
We describe the problem of data dissemination in stream-oriented applications where the required filter is a function of the current state. We call such functions dynamic filters. A state aware data dissemination network (SA-DDN) is proposed to support dynamic filters. Two approaches single-level filtering (SF) and multilevel filter decomposition (MFD) are proposed to facilitate the data dissemination. We show how MFD improves performance over SF. We then describe a realization of SA-DDN on top of an improved bi-directional Chord overlay with a built-in multicast mechanism. An application of stock price monitoring is implemented based on SA-DDN and real life stock quotes are collected to demonstrate the feasibility of our system. Extensive simulations are performed to compare the performance of both approaches and provide insight into the advantages of MFD