Comments on “Adaptive variable structure set-point control ofunderactuated robots” [and reply]

This note points out several technical errors in the above mentioned paper by Su et al. (ibid. vol.44 (1999)). It is shown that the choice of Lyapunov function is inadequate for the system stability analysis, and the asymptotic tracking of the underactuated robot joints is not achievable under certain conditions. In reply, Su addresses, from the comments, some important issues that were not duly emphasised in the paper     

Snakes on the watershed

We present a new approach for object boundary extraction, called the watersnake. It is a two-step snake algorithm whose energy functional is minimized by the dynamic programming method. It is more robust to local minima because it finds the solution by searching the entire energy space. To reduce the complexity of the minimization process, the watershed transformation and a coarse-to-fine strategy are used. The new technique is compared to standard methods for accuracy in synthetic data and is applied to segmentation of white blood cells in bone marrow images     

Control of Feature-point-driven Facial Animation Using a Hypothetical Face

A new approach to the generation of a feature-point-driven facial animation is presented. In the proposed approach, a hypothetical face is used to control the animation of a face model. The hypothetical face is constructed by connecting some predefined facial feature points to create a net so that each facet of the net is represented by a Coon's surface. Deformation of the face model is controlled by changing the shape of the hypothetical face, which is performed by changing the locations of feature points and their tangents. Experimental results show that this hypothetical-face-based method can generate facial expressions which are visually almost identical to those of a real face.     

Suppression of superconductivity in the Er1− x Pr x Ba2Cu3O7−δ

Measurements of electrical resistivity. X-ray diffraction patterns, magnetic susceptibility and thermoelectric power of the Er_1-x Pr _x Ba₂Cu₃O_7- system have been made. The superconducting transition temperature was found to decrease monotonically with praseodymium concentration, x. From the susceptibility data, it was determined that the valence of praseodymium lies between +3 and +4. The thermoelectric power was found to increase with x, and the slopes of dS/dT were negative except for the case x= 0. The. tendency of the thermopower to change with increasing praseodymium concentration has been qualitatively explained using the theory for strongly correlated systems.     

Phase-error-free quadrature sampling technique in the ultrasonic B-scan imaging system and its application to the synthetic focusing system

The quadrature sampling technique as a means of detecting the envelope of RF waveform in the baseband is well known. If this technique is applied to a focused ultrasound imaging system using an array transducer, whether it is a synthetic or nonsynthetic focusing system, unwanted phase terms appear in the expressions of the inphase and quadrature components of the baseband signal when an appropriate delay time is introduced to each channel signal for the purpose of focusing. The expressions of the inphase and quadrature components from the point of focusing are derived and analyzed in detail, and a scheme to eliminate the unwanted phase terms is proposed. The resulting phase-error-free quadrature sampling technique is applied to the synthetic focusing system; a system block diagram together with the simulation and experimental results are presented.     

Real-Time MPEG-2 Video Codec System Using Multiple Digital Signal Processors

A real-time MPEG-2 video codec system, called the KAIST image computing system (KICS), was developed using multiple multimedia video processors (MVP, TMS320C80). The number of computations and optimum implementation of the MPEG-2 algorithm were analyzed for real-time processing. An MVP simulator was used to perform the timing analysis for the real-time MPEG-2 encoding and decoding, and it verified the design of the KICS. Task partitioning and mapping of the MPEG-2 algorithm to multiple MVPs were performed based on load-balancing, minimum data I/O, and the properties of the MVP. The KICS uses five MVPs for MPEG-2 real-time encoding of a main profile at the main level whereas it uses three MVPs for real-time decoding.     

Emergent Properties of a Market-based Digital Library with Strategic Agents

The University of Michigan Digital Library (UMDL) is designed as an open system that allows third parties to build and integrate their own profit-seeking agents into the marketplace of information goods and services. The profit-seeking behavior of agents, however, risks inefficient allocation of goods and services, as agents take strategic stances that might backfire. While it would be good if we could impose mechanisms to remove incentives for strategic reasoning, this is not possible in the UMDL. Therefore, our approach has instead been to study whether encouraging the other extreme—making strategic reasoning ubiquitous—provides an answer.Toward this end, we have designed a strategy (called the p-strategy) that uses a stochastic model of the market to find the best offer price. We have then examined the collective behavior of p-strategy agents in the UMDL auction. Our experiments show that strategic thinking is not always beneficial and that the advantage of being strategic decreases with the arrival of equally strategic agents. Furthermore, a simpler strategy can be as effective when enough other agents use the p-strategy. Consequently, we expect the UMDL is likely to evolve to a point where some agents use simpler strategies and some use the p-strategy.     

熔体物性综合测定仪的控制系统

介绍利用微机制控制和数据处理技术,结合工艺对熔体的物理化学性能进行测量的方法和系统,以及系统的硬件配置,软件组成和功能。该系统能快捷高效地测量出熔体粘度、表面张力、熔渣密度等,具有较高的精确性、可靠性和实用性。     

PVC表面处理剂的研制

介绍了几种表面处理剂对PVC革剥离强度的影响 ,从中选择出最佳表面处理剂A ,并把处理剂A干燥时间对剥离强度的影响作一讨论 ,确定适宜的干燥时间