Implementing a graphical multi-user interface toolkit

Multi-user applications allows users in different locations to simultaneously interact with a common interface. Creating multi-user applications is complicated by issues such as process synchronization, replicated window management, and floor control. As a result, several papers describing toolkits that simplify programming of multi-user applications have appeared in the literature. This paper discusses several low-level issues that must be addressed when implementing such a toolkit. Issues relating to replicated window management, supporting heterogeneous hardware environments, and multi-user event handling are discussed.     

Demonstration of Bidirectional Services Using MPEG‐4 BIFS in Terrestrial DMB Systems

Digital broadcasting technology has developed focusing on multi‐channel/multi‐media, high‐definition quality, and mobility‐support. Recently, there has been a clear trend toward bidirectional service with the convergence between broadcasting and communication. The broadcasting viewer is no longer simply a passive receptor but has also become an information generator. Currently, the digital multimedia broadcasting (DMB) specifications are the major standard for portable digital broadcasting and have been establishing the overall guidelines for bidirectional service using the MPEG‐4 system. While detailed specifications for DMB systems are not well‐established for bidirectional service yet, they share the basic concepts underlying the European Eureka‐147 Digital Audio Broadcasting (DAB) system. This paper develops key scenarios for bidirectional service in DMB, describes the signal transaction of broadcasting and return channels, and demonstrates typical scenarios using binary format for scenes (BIFS) in the MPEG‐4 system.     

Assignment allocation and simulated annealing algorithms for cell formation

In this paper a nonlinear mathematical programming model is developed for cell formation that identifies part families and machine groups simultaneously with no manual intervention or subjective judgement. The objective of the model is minimization of the weighted sum of the voids and the exceptional elements. Changing weights for void and exceptional elements aids the designer with a systematic generation of different solutions, i.e., forming large loose cells or small tight cells. An assignment allocation algorithm (AAA) and a simulated annealing algorithm (SAA) are developed to solve the model. AAA and SAA compare favorably with many well-known procedures for the problems tested. AAA is less computer-intensive and hence large problems with 400 parts and 240 machines were solved with AAA in less than a minute on Sun Sparc station. However, AAA is sensitive to the initial machine grouping solution input to the algorithm. SAA gives consistent results but requires more computational time.     

Hidra: A Hierarchical Instrument for Distributed Real-Time Analysis of Biological Signals

This work presents a locally distributed common bus multiple-processor system intended to support a hierarchical signal processing scheme for biological signal analysis. Each peripheral unit?the so called preprocessor (PP)?executes real-time signal processsing algorithms over data multiplexed in an input bus. The result of this analysis is transferred to a host computer that integrates the received information from the PP's, saves it in disk when necessary, performs higher level data analysis, and interfaces to the user. The processing of electroencelographic (EEG) data will be used as a case study, due to the multidimensional aspects involved.     

蜂窝手机市场和技术发展趋势

从2004年末到2005年初,多数业界观察家预测今后手机业务增长率将减慢,增长速度预测不超过10%,而目前手机业务的最大潜能是为新兴市场开发极低成本手机.这种发展趋势的假设是发达国家市场已经饱和,因此销售量增长应该来自发展中国家初次使用手机的新用户.但后来市场却以15%～20%的惊人速度强势增长,从而在2005年全球手机销售量达到8亿部,而这种增长并不仅限于极低成本手机市场部分.     

Retrieval from semantic memory and its implications for Alzheimer's disease.

In 3 experiments, participants generated category exemplars (e.g., kinds of fruits) while a voice key and computer recorded each response latency relative to the onset of responding. In Experiment 1, mean response latency was faster when participants generated exemplars from smaller categories, suggesting that smaller mental search sets result in faster mean latencies. In Experiment 2, a concurrent secondary task increased mean response latency, suggesting that slowed mental processing results in slower mean latencies. In Experiment 3, the mean response latency of Alzheimer's participants was faster than that of elderly controls, which is consistent with the idea that the semantic memory impairments of Alzheimer's disease patients stem primarily from a reduction in available items (as in Experiment 1) rather than retrieval slowing (as in Experiment 2). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

That's Entertainment! Designing Streaming,Multimedia Web Experiences

This article investigates the use of streaming multimedia narratives in Web entertainment. Based on experience gained during the user-centered design of a Web site for art and culture, evidence is provided that users want and like "less clicking, more watching" Web experiences where the point of view of experts, artists, or celebrities is presented in a narrative form. A study was conducted where users evaluated 2 prototypes of cultural tours that stream continuously for several minutes unless the user chooses to exercise control over the flow or to explore hotlinks that lead to extra information. Those tours were positively evaluated as both entertaining and engaging. By analyzing mouse activity, it was determined that users who interacted more tended to report less entertainment and engagement. It was also found that such "watchable" experiences are not necessarily a solitary experience and can be enjoyed by groups of people. Finally, users see the Web experiences as a highly enriching and accessible way to augment the cultural experiences and performances they enjoy in brick-and-mortar cultural institutions around the world, rather than as a substitute for them.     

Field Testing of Moving Short‐baseline Navigation for Autonomous Underwater Vehicles using Synchronized Acoustic Messaging

This paper presents the results from field testing of a unique approach to the navigation of a fleet of autonomous underwater vehicles (AUVs) using only onboard sensors and information provided by a moving surface ship. The approach, considered moving short‐baseline (MSBL) navigation, uses two transponders mounted on a single surface ship that alternately broadcast acoustic messages containing one of the parameters of the kinematic state of the surface ship. The broadcasts are initiated according to a predefined schedule so that the one‐way travel time (OWTT) of the acoustic messages may be used to determine the range to the transponder. Each AUV in the fleet uses the surface ship state measurements and ranges provided by the acoustic messages in two extended Kalman filters (EKFs) for state estimation. The first EKF merges the intermittent surface ship state measurements with a kinematic model to estimate the state of the surface ship. This is necessary because the presented approach uses 13‐bit acoustic messages as opposed to the more commonly used 32‐byte messages, which allow the full state to be encoded in a single broadcast. The second EKF uses the current surface ship state estimate to properly interpret the acoustic ranges, combining them with a kinematic model to estimate the state of the AUV itself. Numerous MSBL navigation experiments were compared against a more traditional approach using a long‐baseline (LBL) array of transponders and OWTT acoustic ranging. The results of all tests were verified by independent LBL measures of position.