Experiments in design synthesis when behavior is determined by shape

As we rapidly approach the day of transitive materials, made of individual elements that sense and actuate and can be programmed and reprogrammed, it is time to think about how to design things using these new materials. Our roBlocks construction kit toy teaching children about emergent behavior in complex systems serves as an example for investigating the challenges of designing things made of transitive materials. The roBlocks kit comprises heterogeneous modular robotics components that exhibit modularity, one-to-one mapping between form and behavior, and non-hierarchical control; and these features make it appropriate for experimenting with emergent behavior. However, as the numbers of robotic components scales to the orders of magnitude needed to consider them as material these same features also make it difficult to apply traditional methods to design constructions with desired behaviors. To understand this design space we built, the Erstwhile Agent that uses an evolutionary approach to automatically synthesize roBlocks constructions to meet specified desiderata.     

Tax evasion behavior using finite automata: Experiments in Chile and Italy

In this paper, we use a Moore Automata with Binary Stochastic Output Function in order to capture the extensive decision regarding tax evasion made by subjects in experiments run in Chile and Italy. Firstly, we show how an hypothesis about subject behavior is converted into an automaton, and how we compute the probabilities of evading for every state of an automaton. We use this procedure in order to look for the automaton which is able to anticipate the highest number of decisions made by the subjects during the experiments. Finally, we show that automata with few states perform better than automata with many states, and that the bomb-crater effect described in Mittone (2006) is a well identified pattern of behavior in a subset of subjects.     

基于行为描述的Web服务组合兼容性检查*

定义了服务的基调视图和行为视图,设计了将Web服务行为转换为π演算进程表达的建模方法,并给出了实现服务视图向π演算进程自动转换的算法;最后借助π演算的操作语义和形式化推理技术实现了对Web服务组合时的兼容性进行检查。     

Dynamics behavior of flat glass panels under impact conditions: Experiments and numerical modeling

Response of brittle plate‐like structures such as glass panels to impact loads has been the subject of many research studies. Different compositions of glass are used in wide variety of applications in daily life. Of interest in this study are the glass panels that are used in consumer electronics devices such as mobile phones, tablets, and televisions that help to protect the displays from every day wear and tear. Therefore, the requirement of this glass to resist scratches, drop impacts, and bumps from everyday use leads to the importance of investigation of the glass response under dynamic impact loading. Ball drop test is a widely accepted test for impact reliability in the industry. The test specifies the impact energy threshold as a qualification and prediction metric. Use of energy as the key parameter in impact testing is limited, because it does not account for the time spent in contact during the impact event. This study attempts to establish a reliable metric for impact testing based on a momentum change. The deformation and the strain of the glass will be obtained by the digital image correlation system, while the rebound velocity will be measured with the high‐speed cameras. The global and local measurements are conducted to verify the accuracy of the experimental results. Finite element analysis is conducted using ABAQUS to provide a comprehensive understanding of the dynamic response of the glass. Constitutive relationship for a tape, a hyperelastic material, is developed in this study. Good correlation in deflection time history is obtained between the measurements and predictions.     

一种快速易用的基于行为描述的服务组合方法*

为了提高基于行为描述的服务组合方法的易用性和效率,首先对服务和服务请求进行建模;然后使用一个三层图模型组织服务之间的关系,并基于这个三层图模型提出一种快速易用的服务组合方法;最后通过实例说明了该方法的组合过程,并从理论上分析了该方法的时间复杂度。理论分析显示该方法具有较好的效率。     

Experiments in optimizing FP

FPOPT, a globally optimizing compiler for FP, was built to study the efficiency of compiling a functional programming language by translating it into an intermediate language and then optimizing that intermediate language. The FPOPT system, the design of the intermediate language and the optimizations performed are described. The relative effectiveness of these optimizations, singly and in combinations, are compared using an instrumented version of FPOPT.<>     

Experiments in contact control

This article describes the implementation, experimentation, and application of contact control schemes for a 7-DOF Robotics Research arm. The contact forces and torques are measured in the sensor frame by the 6-axis force/torque sensor mounted at the wrist, are compensated for gravity, and then are transformed to the tool frame in which the contact task is defined and executed. The contact control schemes are implemented on the existing robot Cartesian position control system at 400Hz, do not require force rate information, and are extremely simple and computationally fast. Three types of contact control schemes are presented: compliance control, force control, and dual-mode control. In the compliance control scheme, the contact force is fed back through a lag-plus-feedforward compliance controller so that the end-effector behaves like a spring with adjustable stiffness; thus the contact force can be controlled by the reference position command. In the force control scheme, a force setpoint is used as the command input and a proportional-plus-integral force controller is employed to ensure that the contact force tracks the force setpoint accurately. In the dual-mode control scheme, the end-effector approaches and impacts the reaction surface in compliance mode, and the control scheme is then switched automatically to force mode after the initial contact has been established. Experimental results are presented to demonstrate contact with hard and soft surfaces under the three proposed control schemes. The article is concluded with the application of the proposed schemes to perform a contact-based eddy-current inspection task. In this task, the robot first approaches the inspection surface in compliance control until it feels that it has touched the surface, and then automatically levels the end-effector on the surface. The robot control system then transitions to force control and applies the desired force on the surface while executing a scanning motion. At the completion of the inspection task, the robot first relaxes the applied force and then retracts from the surface. © 1996 John Wiley & Sons, Inc.     

Experiments in interpretation-guided segmentation

This paper presents a new approach for integrating the segmentation and interpretation phases of scene analysis. Knowledge from a variety of sources is used to make inferences about the interpretations of regions, and regions are merged in accordance with their possible interpretations.The deduction of region interpretations is performed using a generalization of Waltz's filtering algorithm. Deduction proceeds by eliminating possible region interpretations that are not consistent with any possible interpretation of an adjacent region. Different sources of knowledge are expressed uniformly as constraints on the possible interpretations of regions. Multiple sources of knowledge can thus be combined in a straightforward way such that incremental additions of knowledge (or equivalently, human guidance) will effect incremental improvements in performance.Experimental results are reported in three scene domains, landscapes, mechanical equipment, and rooms, using, respectively, a human collaborator, a geometric model and a set of relational constraints as sources of knowledge. These experiments demonstrate that segmentation is much improved when integrated with interpretation. Moreover, the integrated approach incurs only a small computational overhead over unguided segmentation.Applications of the approach in cartography, photointerpretation, vehicle guidance, medicine, and motion picture analysis are suggested.     

Experiments in multirobot coordination

Consequent to previously published theoretical work by Marshall, Broucke, and Francis, this paper summarizes the apparatus and results of multirobot coordination experiments conducted at the University of Toronto Institute for Aerospace Studies. These experiments successfully demonstrate the practicality of cyclic pursuit as a distributed control strategy for multiple wheeled-robot systems. The pursuit-based coordination algorithm was found to be surprisingly robust in the presence of unmodelled dynamics and delays due to sensing and information processing. Moreover, the findings of this research not only bode well for continuing research on pursuit-based coordination strategies, but also for other cooperative multirobot control techniques employing similar local interactions.     

Experiments in haptic-based authentication of humans

With the rapid advancement of the technological revolution, computer technology such as faster processors, advanced graphic cards, and multi-media systems are becoming more affordable. Haptics technology is a force/tactile feedback technology growing in disciplines linked to human–computer interaction. Similar to the increasing complexity of silicon-based components, haptics technology is becoming more advanced. On the other hand, currently available commercial haptics interfaces are expensive, and their application is mostly dedicated to enormous research projects or systems. However, the trend of the market is forcing haptic developers to release products for use in conjunction with current keyboards and mice technologies. Haptics allows a user to touch, fell, manipulate, create, and/or alter simulated three-dimensional objects in a virtual environment. Most of the existing applications of haptics are dedicated to hone human physical skills such as sensitive hardware repair, medical procedures, handling hazardous substances, etc. These skills can be trained in a realistic virtual world, and describe human behavioural patterns in human–computer interaction environments. The measurement of such psychomotor patterns can be used to verify a person’s identity by assessing unique-to-the-individual behavioural attributes. This paper explores the unique behaviour exhibited by different users interacting with haptic systems. Through several haptic-based applications, users’ physical attributes output data from the haptic interface for use in the construction of a biometric system.

Experiments in program verification using Event-B

The Event-B method can be used to model all sorts of discrete event systems, among them sequential programs. In this article we describe our experiences with using Event-B by way of two examples. We present a simple model of a factorial program, explaining the method, and a more intricate model of the Quicksort algorithm, providing some insights into strengths and weaknesses of Event-B. The two models are interspersed with our observations and some suggestions of how, we believe, Event-B could evolve. This evaluation of Event-B is intended to serve for determining directions for the evolution of Event-B and judging progress. It is our hope that the observations and suggestions can also be put to use for similar modelling formalisms, such as Z, ASM or VDM.     

第三代移动通信技术试验进展简况

世界经济低靡使整个电信行业遇到前所未有的发展困境．也直接影响着3G的实用化进程。此外．3G业务及市场条件．特别是3G技术本身的成熟性，成为决定其能否大规模商用的基础。     

Dynamic State Charts: composition and coordination of complex robot behavior and reuse of action plots

Support for separation of roles is decisive towards a successful business ecosystem where various stakeholders with dedicated expertises network and collaborate. However, it depends on means for composition(system of systems, reuse of black boxes). This paper proposes Dynamic State Charts as an extension of state charts for composition and coordination of complex robot behavior which is one of the challenges in service robotics. Their states allow to refine their content by choosing from a set of alternative matching state instances for robust task execution and to manage the complexity of real-world tasks. Dynamic State Charts allow reuse and can be bundled with software components and are provided in a repository (idea of an “robot app store”) as a step towards composition and separation of roles as necessary for a business ecosystem in service robotics. The approach is demonstrated in a practical application with a service robot.     

DAVIC and Interoperability Experiments

To promote the development and deployment of broadband audio visual services, DAVIC has been working on specifying the standards and interfaces for end-to-end systems providing services to consumers over broadband networks. DAVIC specifies tools to provide these broadband services. Since the tools specified by DAVIC are standardized/developed by independent organizations, it is important to verify that the complete system works when these tools are used together. An interoperability event was organized by Columbia University for this very purpose. In this paper we first introduce DAVIC and DAVIC systems and then give details of the interoperability event: the motivation, goals, and results.     

Experiments with semantic paramodulation

A semantic restriction is presented for use with paramodulation in automated theorem-proving programs. The method applies to first-order formulas with equality whole clause forms are Horn sets. In this method, an interpretation is given to the program along with the set of clauses to be refuted. The intention is to have the interpretation serve as an example to guide the search for a refutation. The semantic restriction was incorporated into an existing automated theorem-proving program, and a number of experiments were conducted on theorems in abstract algebra. Semantic paramodulation is an extension of set-of-support paramodulation. A comparison of the two strategies was used as the basis for experimentation. The semantic searches performed markedly better than the corresponding set-of-support searches in many of the comparisons. The semantic restriction seems to make the program less sensitive to the choice of rewrite rules and supported clauses.     

CoABS Grid Scalability Experiments

The CoABS Grid is middleware that integrates heterogeneous agent-based, object-based, and legacy systems. It includes a method-based application programming interface to register agents, advertise agent capabilities, discover agents based on their capabilities, and send messages between agents. Agent registration and discovery are reliant on one or more lookup services. The experiments discussed in this paper investigate how timing of sequential agent registration and lookup varies as the total number of registered agents increases. No degradation in performance was observed in experiments with up to 10,000 agents for lookup. Minimal degradation in registration time was observed as the number of registered agents increased. Further experiments are planned.     

Experiments in Cost Analysis of Java Bytecode

Recently, we proposed a general framework for the cost analysis of Java bytecode which can be used for measuring resource usage. This analysis generates, at compile-time, cost relations which define the cost of programs as a function of their input data size. The purpose of this paper is to assess the practicality of such cost analysis by experimentally evaluating a prototype analyzer implemented in Ciao. With this aim, we approximate the computational complexity of a set of selected benchmarks, including both well-known algorithms which have been used to evaluate existing cost analyzers in other programming paradigms, and other benchmarks which illustrate object-oriented features. In our evaluation, we first study whether the generated cost relations can be automatically solved. Our experiments show that in some cases the inferred cost relations can be automatically solved by using the Mathematica system, whereas, in other cases, some prior manipulation is required for the equations to be solvable. Moreover, we experimentally evaluated the running time of the different phases of the analysis process. Overall, we believe our experiments show that the efficiency of our cost analysis is acceptable, and that the obtained cost relations are useful in practice since, at least in our experiments, it is possible to get a closed form solution.     

仿真实验在计算机网络教学中的应用研究

计算机网络是计算机及相关专业的一门重要课程,而计算机网络的教学具有很强的实践性,需要有大量的网络设备进行实验实训教学。该文分析了目前计算机网络教学中遇到的常见问题,探讨了使用模拟机软件和交换路由模拟软件进行仿真实验在计算机网络教学中的应用。