The application of wireless local area network technology to the control of mobile robots

This paper describes a communications and control infrastructure for distributed mobile robotics, which makes use of wireless local area network (WLAN) technology and Internet Protocols (IPs). The use of commercial off-the-shelf (COTS) hardware and software components, and protocols, results in a powerful platform for conducting experiments into collective or co-operative robotics. Standard Transmission Control Protocol/Internet Protocol (TCP/IP) compatible applications programming interfaces (APIs) allow for rapid and straightforward development of applications software. Further, the message bandwidth available from WLAN interfaces (1–2 Mbits/s) facilitates multi-robot experiments requiring high data rates, for instance in robot vision or navigation. The infrastructure described is equally applicable to tele-operated mobile robots.     

Geometric constraint satisfaction using optimization methods

The numerical approach to solving geometric constraint problems is indispensable for building a practical CAD system. The most commonly-used numerical method is the Newton–Raphson method. It is fast, but has the instability problem: the method requires good initial values. To overcome this problem, recently the homotopy method has been proposed and experimented with. According to the report, the homotopy method generally works much better in terms of stability. In this paper we use the numerical optimization method to deal with the geometric constraint solving problem. The experimental results based on our implementation of the method show that this method is also much less sensitive to the initial value. Further, a distinctive advantage of the method is that under- and over-constrained problems can be handled naturally and efficiently. We also give many instructive examples to illustrate the above advantages.     

A survey of modern knowledge modeling techniques

A major characteristic regarding developments in the broad field of artificial intelligence (AI) during the 1990s has been an increasing integration of AI with other disciplines. A number of other computer science fields and technologies have been used in developing intelligent systems, starting from traditional information systems and databases, to modern distributed systems and the Internet. This paper surveys the knowledge modeling techniques that have received most attention in recent years among developers of intelligent systems, AI practitioners and researchers. The techniques are described from two perspectives, theoretical and practical. Hence the first part of the paper presents major theoretical and architectural concepts, design approaches, and research issues. The second part deals with several practical systems, applications, and ongoing projects that use and implement the techniques described in the first part.     

A self-tuning microcontroller-based glass measuring instrument

This paper describes the development and implementation of a self-tuning microcontroller-based instrument for measuring different thicknesses of glass and glass substitutes. The instrument’s hardware was successfully tested in the laboratory on coated and uncoated glass under a variety of conditions. It is designed to provide high performance and high precision measuring capability to the system user. The obtained experimental data suggest that the proposed instrument surpasses existing techniques in its accuracy, reliability, simple operation, safety and measuring capability.     

The interdeparture time distribution for each class in the ∑Mi/Gi/1 queue with set-up times and repeated server vacations

This paper studies the interdeparture time distribution of one class of customers who arrive at a single server queue where customers of several classes are served and where the server takes a vacation whenever the system becomes empty or is empty when the server returns from a vacation. Furthermore, the first customer in the busy period is allowed to have an exceptional service time (set-up time), depending on the class to which this customer belongs. Batches of customers of each class arrive according to independent Poisson processes and compete with each other on a FIFO basis. All customers who belong to the same class are served according to a common generally distributed service time. Service times, batch sizes and the arrival process are all assumed to be mutually independent. Successive vacation times of the server form independent and identically distributed sequences with a general distribution.For this queueing model we obtain the Laplace transform of the interdeparture time distribution for each class of customers whose batch size is geometrically distributed. No explicit assumptions of the batch size distributions of the other classes of customers are necessary to obtain the results.The paper ends by showing how the mathematical results can be used to evaluate a protocol that controls access to a shared medium of an ATM passive optical network. The numerical results presented in the last section of this paper show that the bundle spacing principle that is used by the permit distribution algorithm of this protocol introduces high delays and in many cases also more variable interdeparture times for the ATM cells of individual connections. An alternative algorithm is proposed that does not cope with these performance short comings and at the same time conserves the good properties of the protocol.     

Workload bounds in fluid models with priorities

In this paper we establish upper and lower bounds on the steady-state per-class workload distributions in a single-server queue with multiple priority classes. Motivated by communication network applications, the model has constant processing rate and general input processes with stationary increments. The bounds involve corresponding quantities in related models with the first-come first-served discipline. We apply the bounds to support a new notion of effective bandwidths for multi-class systems with priorities. We also apply the lower bound to obtain sufficient conditions for the workload distributions to have heavy tails.     

Dynamic behavior of the robust decorrelation process

In this short paper, we discuss the dynamic behavior of a decorrelation process. We analyze the global convergence and give the optimal robust step size for fast convergence. Simulation results corroborate our theoretical analysis.     

Long-term follow-up evaluation in HCV chronic hepatitis treated with alpha-2b interferon. A comparison of two protocols

OBJECTIVE: To compare prospectively the concordance between the diagnosis of dementia based on clinical criteria and using the DAT Inventory. DESIGN, SETTING, AND PARTICIPANTS: A prospective study of 81 consecutive patients referred to a Memory Clinic. Only patients for whom a definitive diagnosis of dementia was established after 8 to 20 months follow-up were retained in the study (n = 76). MEASUREMENTS: The sensitivity, specificity, positive and negative predictive values, and overall diagnostic accuracy of the DAT Inventory were calculated. Kappa values were also computed. RESULTS: Based on all patients (n = 76), sensitivity and specificity were 71% and 95%, respectively, with 98% positive prediction, 56% negative prediction, 78% overall accuracy, and kappa of 0.54. Of 21 cases not meeting NINCDS/ADRDA criteria for DAT, one patient with multi-infarct dementia was misclassified as DAT on the DAT Inventory. Of 55 DAT cases (NINCDS/ADRDA criteria), 16 patients, predominantly very mild or mixed cases, were classified as non-DAT on the DAT Inventory. When mixed, very mild, and borderline cases were excluded (remaining n = 54), DAT Inventory sensitivity increased to 94%, and specificity remained unchanged at 95%, with 97% positive and 91% negative prediction, 94% overall accuracy, and kappa of 0.88. CONCLUSIONS: In general, scores above the designated cutoff point (> 14/20) on the DAT Inventory are consistent with a clinical diagnosis of DAT (NINCDS/ADRDA criteria). Concordance is best in cases of mild to moderate dementia (Clinical Dementia Rating 1-2). The Inventory is less discriminating as a differential diagnostic instrument in cases of very mild dementia, atypical presentations of DAT, or in cases of mixed pathology.     

PRELIMINARY INVESTIGATION ON THE EFFECT OF FOAM STABILIZERS ON THE PHYSICAL CHARACTERISTICS AND RECONSTITUTION PROPERTIES OF FOAM-MAT DRIED SOYMILK

Soymilk, a colloidal dispersion obtained by wet milling of soya bean (Glycine max (L) Merill), was subjected to the foam-mat drying process at 65°C using two foam stabilizers namely, carboxy methyl cellulose (CMC) and glyceryl distearate (GDS) at 5, 10 and 15% levels. While CMC did not produce a stable foam at any of the levels used, it was however, found that a minimum of 10% GDS was required to produce a stable foam. The physical characteristics and reconstitution properties of 10% GDS foamed soymilk powder and 15% GDS foamed soymilk powder were found to be similar but better than those of unfoamed soymilk powder and inferior to those of a spray dried powder sample.     

Model-driven monitoring support for the multi-view performance analysis of parallel embedded applications

This paper describes an approach to carry out performance analysis of parallel embedded applications. The approach is based on measurement, but in addition, the idea of driving the measurement process (application instrumentation and monitoring) by a behavioral model is introduced. Using this model, highly comprehensible performance information can be collected. The whole approach is based on this behavioral model, one instrumentation method and two tools, one for monitoring and the other for visualization and analysis. Each of these is briefly described, and the steps to carry out performance analysis using them are clearly defined. They are explained by means of a case study. Finally, one method to evaluate the intrusiveness of the monitoring approach is proposed, and the intrusiveness results for the case study are presented.