The Video-On-Demand Trial in Taiwan: A Partially DAVIC Compliant System

This paper reviews the Video-On-Demand technical trial conducted by Computer & Communication Research Laboratories in Taiwan. This trial is one of the key realization of Taiwan's National Information Infrastructure. The primary goal is to provide a testbed and platform for new product development, interoperability test, and interactive multimedia applications. It also explores the technical difficulties from which experiences can be gained for future large scale deployment. Open system and end-to-end system are the most important requirements of the VOD system in this trial. Open system allows a variety of video servers and set-top boxes to be integrated into the system while end-to-end system requires system integration know-how.An overview of the Video-On-Demand system is provided in this paper. The architecture of the video server, delivery network and set-top box will be examined. The system integration issues including content preparation will also be discussed.     

EduMiner: Using text mining for automatic formative assessment

Formative assessment and summative assessment are two widely accepted approaches of assessment. While summative assessment is a typically formal assessment used at the end of a lesson or course, formative assessment is an ongoing process of monitoring learners’ progresses of knowledge construction. Although empirical evidence has acknowledged that formal assessment is indeed superior to summative assessment, current e-learning assessment systems however seldom provide plausible solutions for conducting formative assessment. The major bottleneck of putting formative assessment into practice lies in its labor-intensive and time-consuming nature, which makes it hardly a feasible way of achievement evaluation especially when there are usually a large number of learners in e-learning environment. In this regard, this study developed EduMiner to relieve the burdens imposed on instructors and learners by capitalizing a series of text mining techniques. An empirical study was held to examine effectiveness and to explore outcomes of the features that EduMiner supported. In this study 56 participants enrolling in a “Human Resource Management” course were randomly divided into either experimental groups or control groups. Results of this study indicated that the algorithms introduced in this study serve as a feasible approach for conducting formative assessment in e-learning environment. In addition, learners in experimental groups were highly motivated to phrase the contents with higher-order level of cognition. Therefore a timely feedback of visualized representations is beneficial to facilitate online learners to express more in-depth ideas in discourses.     

多客户协同特征造型系统中的冲突解决

基于对协同环境下特征操作的分析,通过动态调整特征操作造型指令并定义一种基于非置锁机制的设计流程,以解决多客户协同设计中的冲突问题,克服常规令牌传递策略缺乏灵活性的弊端,实现了一个基于文中算法的原型系统,设计实例验证了该系统的灵活性和高效性。     

Video Polyp Segmentation: A Deep Learning Perspective

Machine Intelligence Research - We present the first comprehensive video polyp segmentation (VPS) study in the deep learning era. Over the years, developments in VPS are not moving forward with...     

Location determination of mobile devices for an indoor WLAN application using a neural network

Due to the popularity of location-based services, determining the location of a device at all times has become a subject of great interests. Although many GPS-based applications have been developed and successfully deployed in various fields, their applicabilities are hindered by the obstruction of the objects in the environment. Essentially, as satellite signals cannot penetrate the walls of buildings, the coverage of GPS systems is limited to outdoor environments. To fully exploit the benefit of location-based services, approaches that determine the location of a device in indoor environments need to be established. This study presents a novel location determination mechanism that uses an indoor WLAN and back-propagation neural network (BPN). A museum is taken as the context of the example indoor environment. Location determination is achieved using the combined strengths of 802.11b wireless access signals. With a significant number of access points (APs) installed in the museum, hand-held devices can sense the strengths of the signals from all APs to which the devices can connect. Using a back-propagation network, device locations can be estimated with sufficient accuracy. A novel adaptive algorithm is implemented for enhancing the accuracy of the estimation.

Lax–Friedrichs Multigrid Fast Sweeping Methods for Steady State Problems for Hyperbolic Conservation Laws

Fast sweeping methods are efficient Gauss–Seidel iterative numerical schemes originally designed for solving static Hamilton–Jacobi equations. Recently, these methods have been applied to solve hyperbolic conservation laws with source terms. In this paper, we propose Lax–Friedrichs fast sweeping multigrid methods which allow even more efficient calculations of viscosity solutions of stationary hyperbolic problems. Due to the choice of Lax–Friedrichs numerical fluxes, general problems can be solved without difficult inversion. High order discretization, e.g., WENO finite difference method, can be incorporated to achieve high order accuracy. On the other hand, multigrid methods, which have been widely used to solve elliptic equations, can speed up the computation by smoothing errors of low frequencies on coarse meshes. We modify the classical multigrid method with regard to properties of viscous solutions to hyperbolic conservation equations by introducing WENO interpolation between levels of mesh grids. Extensive numerical examples in both scalar and system test problems in one and two dimensions demonstrate the efficiency, high order accuracy and the capability of resolving singularities of the viscosity solutions.     

Two‐phase scale‐based reduction method for fulfilling monitoring service on mobile devices

One of the general location‐based services (LBSs) is the monitoring of real‐time locations of moving objects. When the number of moving objects is large and the task of monitoring is carried out on mobile devices, the monitoring service suffers from constraints of screen size, computing speed, and network bandwidth. In the present paper, a two‐phase scale‐based reduction method (SRM) consisting of a zoom phase and a mosaic phase, is proposed to overcome these constraints. The zoom phase reduces the original monitoring area which, in turn, undergoes further reduction in the mosaic phase. The performance was measured with the use of two ratios: the reduction ratio (RRatio) and the transmission ratio (TRatio). From the experimental results, the lowest RRatio was 52%, i.e. almost half of the original data size was reduced. The lowest average TRatio was also 52% for the worst case, i.e. the entire original monitoring area was displayed on the mobile device. Moreover, the display time was shortened from 14.3 to 0.7 s. These results show that the use of the two‐phase SRM is practical and efficient when applied to the monitoring service on mobile devices. Copyright © 2006 John Wiley & Sons, Ltd.     

Feasibility of bioremediation of trichloroethylene contaminated sites by nitrifying bacteria through cometabolism with ammonia.

The autotrophic ammonia-oxidizing bacteria (Nitrosomonas sp.) are able to dechlorinate trichloroethylene (TCE) through cometabolism using ammonia (NH(3)) as a growth substrate. Cometabolic kinetics models suggest that TCE is a potent competitive inhibitor of NH(3) oxidation because it competes with NH(3) for oxidation by the enzyme of ammonia monooxygenase (AMO). In this study, an enriched culture of nitrifying bacteria was used to investigate the efficiencies of cometabolism of TCE by AMO. In addition, the relationships among specific growth substrate (NH(3)) utilization rate (qNH(3)), specific nongrowth substrate (TCE) cometabolic rate (qTCE), NH(3) and TCE concentrations, and NH(3)/TCE and TCE/NH(3) ratios were also analyzed. We found that the relationships between qNH(3) and NH(3) for the systems with and without TCE followed the Alvarez-Cohen competitive inhibition model and Monod model, respectively. Our results demonstrate that TCE could be cometabolized in a nitrification system when sufficient oxygen and NH(3)200 microg/l) were also found to show inhibitory effects towards NH(3) oxidation in enriched nitrifying culture. We also found that the NH(3)/TCE ratio rather than TCE concentrations alone exhibited strong correlation with qNH(3), much the same as the Ely activity recovery model presented. Our results suggest that the relationship between qTCE and TCE concentrations followed the Oldenhuis enzyme inactivation model for systems without NH(3).     

Morphology of and surface modification by TiO2 deposits on a porous ceramic substrate

We investigate the morphology of and surface modification by titanium dioxide (TiO₂) deposits on porous ceramic substrates placed in a horizontal, tubular, hot-wall, atmospheric pressure chemical vapor deposition (CVD) reactor with titanium tetraisoperoxide (TTIP) as the precursor. The TiO₂ particles are produced from TTIP through two routes: first by thermal decomposition which then kicks off hydrolysis. The deposit characteristics is found to be location dependent. Those at the reactor entrance and exit are different from that within the reactor. Within the reactor, the deposit characteristics is further found to depend strongly on the deposition temperature (T_d) and is almost independent of the flow-rate and concentration of the reactant. With a T_d of about 380 °C, the deposited TiO₂ forms a forest-like structure with poor adhesivity to the substrate and results in an insignificant pore size reduction for the substrate. If T_d drops down to about 300 °C, the deposited TiO₂ forms a rock-packing structure with good adhesivity to the substrate and can reduce the pore size of the substrate from about 1–2 m down to about 64 nm. At both the reactor entrance and exit, the deposited TiO₂ are loosely-packed spherical particles of average diameter of 140–400 nm. A theory, based on whether or not the reaction is gas-phase or surface dominated, is proposed to explain the dramatic effect of T_d.     

A Behavior-based Classification and Retrieval Technique for Object-oriented Specification Reuse

This paper presents a classification and retrieval technique for object-oriented specification reuse, based on the assumption that existing specifications exhibiting behaviors similar to that of the system under development are appropriate for reuse. Existing specifications are classified and retrieved according to the semantic networks abstracted from their behaviors. Since semantic networks attach semantic meanings to certain degrees of detail, our technique is rather precise. Primary behavior is used to classify specifications because it can be obtained in the early phases of system analysis. Therefore, our technique allows early reuse. Moreover, subspecifications and classes of existing specifications are classified independently so that they can be retrieved for reuse separately. Thus, our technique encourages reusing subspecifications as well as classes. Since a subspecification is composed of classes and their relationships, reusing it corresponds to reusing all those classes and relationships. A technique that reuses subspecifications as well as classes is thus expected to save more time than those that reuse only classes.