Cooperative Object Research Articles

異なるタスクを持つ複数ロボットによる単一物体の協調搬送

A cooperative control method for multiple robots of single object transportation is proposed, which is applicable to unknown environment. In this method, all robots are controlled by the same algorithm, and they can have different objective tasks simultaneously. A task is expressed as the desired position of the object and the associated weight matrix, and each robot can set its own desired position and weight matrix independently of the other robots' tasks. By the proposed method, the robots can cooperatively transport the object to the composite desired position which is the weighted mid point of the desired positions set by all robots, without communicating their tasks with one another. The forces between the robots and the object are controlled as equally as possible during transportation. Furthermore, the internal forces can be suppressed only if some robots in danger of applying large forces broadcast on/off signal to the other robots. Accordingly, this method requires little amount of real-time communication among the robots and does not depend on the number of robots. Owing to these features, the method can deal with the situation where one robot has “path tracking task” and another robot which detects an obstacle has “obstacle avoidance task”; that allows cooperative object transportation with obstacle avoidance in unknown environment. The effectiveness and usefulness of the method are ascertained by computer simulation and experiment.

2P2-L6 異なる目標位置を持った複数ロボットによる単一物体の協調搬送 : 過大な力の抑制法(54. 複数ロボットの協調)

2P2-L6 異なる目標位置を持った複数ロボットによる単一物体の協調搬送 : 過大な力の抑制法(54. 複数ロボットの協調)

Dynamo: design, implementation, and evaluation of cooperative persistent object management in a local area network

In light of advances in processor and networking technology, especially the emergence of network attached disks, the traditional client-server architecture of persistent storage systems has become suboptimal for many computation/data intensive applications. In this paper, we introduce a revised architecture for persistent object management employing network attached storage: the dynamic object server environment (Dynamo). Dynamo introduces two main architectural innovations: (1) to provide high scalability, the object management functions are mainly performed cooperatively by the clients in the system. Furthermore, data is transferred directly to the client's cache from network-attached disks, thus avoiding copies from a disk to the server buffer and then over the network to the client. Other systems have an a priori assignment of ‘object management’ functions to specific nodes; (2) Dynamo uses a cooperative cache management which employs a decentralized lottery-based page replacement strategy with a novel technique which attempts to put a page replaced from one node into the cache of another node which is likely to access the page in the near future. We show via performance benchmarks run on the Dynamo system and simulation results how this architecture increases the system's adaptability, scalability and cost performance. Copyright © 2000 John Wiley & Sons, Ltd.

Development of a charged-particle nuclear reaction data retrieval system on Intelligent Pad: CONTIP

A newly designed retrieval system of charged-particle nuclear reaction data (CPND) is developed on the IntelligentPad architecture. NRDF (Nuclear Reaction Data File), which is a kind of CPND compilation, is applied as an example. The authors designed the network-based (client-server) retrieval system. The server system is constructed on a UNIX workstation with a relational database; the client system is built on a Microsoft Windows PC using an IntelligentPad software package. The system is called CONTIP, which is an abbreviation of ‘Creative, Cooperative and Cultural Objects for Nuclear data and Tools on IntelligentPad’. CONTIP will be developed to realise effective utilisation of nuclear reaction data: (i) reproduction, re-edit, reuse, (ii) circulation, coordination and evolution and (iii) knowledge discovery.

Cooperative Object Transportation on a 2-D Plane by a Parallel Biwheel Vehicle Driven with a Stepping Motor.

A control scheme of cooperative object transportation on a 2-D plane with two parallel biwheel vehicles(PBVs), whose wheels are driven with stepping motors individually, is described. The posture of each PBV is stabilized with a discrete time sliding mode regime and the reaction force from the transporting object is regulated with a fuzzy logic controller to hold the object between PBVs. As the forward side PBV runs along a reference pass, the backward side PBV is controlled so as to follow the forward one with an appropriate velocity and curvature which are estimated from the reaction force deviation and difference. With a smooth "S"-bent reference pass of 1.2m in pass length and of 2.5m-1 in maximum curvature, the PBVs can transport a block of 50g in weight successfully with the proposed control scheme. The steering characteristics of the PBV are also discussed, where an open loop control method shows excellent steering performance for both spin and pivot turns. These results are brought from the inherent control characteristic of the stepping motor.

Blended payment methods in physician organizations under managed care.

Independent practice associations (IPAs) are developing new methods of physician reimbursement to balance the objectives of encouraging individual productivity and clinical cooperation. The economic literature on payment incentives, derived from nonhealth industries, predicts that methods blending elements of fee-for-service and capitation will outperform exclusive reliance on either form of payment. To identify emerging payment methods within IPA physician groups that contract with managed care organizations. Case studies of 7 large IPAs in the San Francisco, Calif, metropolitan region that served 826000 health maintenance organization (HMO) patients during the summer and fall of 1998. Payment methods of IPAs for primary care physicians, specialists, and physicians grouped by specialty department within the overall IPA structure. All the IPAs contracted with multiple HMOs for the full range of primary and specialty care physicians' services but paid member physicians using methods that blended elements of fee-for-service and subcapitation. For primary care, most IPAs used monthly capitation adjusted for patient age, sex, and selected diagnoses, supplemented with fee-for-service payment for a wide range of visits and procedures, including patient visits in subacute, skilled nursing facility, emergency department, or home settings; for preventive care services; for office procedures requiring expensive supplies; and, most importantly, for borderline primary care procedures that either could be performed directly or referred to specialty care. All the IPAs paid specialty departments on a capitated basis and delegated to the departments responsibility for allocating the budget among individuals. Allocation mechanisms for individual specialists included adjusted fee-for-service, referral-based capitation, and blends of both. Our results and case studies indicate that IPAs are developing payment methods that blend elements of fee-for-service and capitation in innovative ways for primary care and specialty physicians.

Cooperative transportation by two four-legged robots with implicit communication

In this paper, we show cooperative object transportation by two four-legged robots. To realize cooperative transportation with autonomy, we adopt implicit communication based cooperation. Each robot uses only its own sensors to estimate the state of a task. With this method, people can attend to the cooperation system without any changes. We will show an algorithm and two experiments; one is by two legged robots and the other is by one robot and a human.

Reaction Force Control and Cooperative Transportation by a Parallel Biwheel Vehicle Driven with a Stepping Motor.

Reaction force control of a parallel biwheen vehicle (PBV), which is driven with two stepping motors in an open loop mode, is described on purpose to hold and/or to transport objects with it. The PBV is an inverted pendulum type unstable vehicle, hence its posture has been regulated by a discrete time sliding mode controller. The reaction force is generated by contacting and leaning the PBV toward objects and the magnitude of the reaction force is controlled with a fuzzy logic controller. Nonlinear control output of the fuzzy logic controller is suitable for achieving a quick and calm force response at the same time. For a square wave force reference up to 1N, the reaction force of the PBV can quickly follow the reference signal without remarkable overshoot and the PBV can keep steady reaction force. The control performance is discussed in detail and is compared with that of PI force control. As an application, cooperative object support and transportation with PBVs are also demonstrated.

ACP–EU trade cooperation after 2000: an assessment of reciprocal trade preferences

The establishment of the World Trade Organisation (WTO) in 1995 reflected and reinforced significant shifts in global orthodoxies in favour of the liberalisation of world trade, and posed problems for trading arrangements such as the Lome Conventions between the European Union (EU) and the 70 African, Caribbean and Pacific (ACP) states, which had initially been established in the very different setting of the mid-1970s. Integral to the Lome Conventions has been the principle of non-reciprocity, under which the EU offered preferential conditions for access to its markets by products originating in the ACP states, without any requirement for reciprocal concessions (other than most-favoured-nation status) by the ACP. These preferences are due to expire with the 4th Lome Convention in February 2000. Because they are non-reciprocal, these preferences cannot qualify under Article XXIV of the General Agreement on Tariffs and Trade (GATT) of 1947. Being available only to a particular group of developing countries, they are discriminatory and cannot be regarded as being covered by Part IV of the GATT, or the Enabling Clause of 1979, since these measures only sanction special, differential and preferential treatment for all developing countries. As a result of the changed climate of opinion in the World Trade Organisation (WTO), emphasising the obligation of members to bring their trade measures into conformity with WTO disciplines, the EU sought and obtained a waiver from Article I (principle of non-discrimination) for the remaining duration of the Convention, leaving open the arrangements to be put into effect after 2000.In the public discussions and consultations on a successor arrangement to Lome, the European Commission has emphasised the need for such an arrangement to be compatible with WTO requirements, so as to ensure the legal security of preferences. It is therefore envisaged that Lome preferences will be available only to the least developed countries (LLDCs), but will be generalised to all of the least developed countries, including for example Bangladesh, Bhutan, Cambodia, Lao D.R., Maldives, Nepal and Yemen, and not just to members of the ACP Group. The Commission has proposed that the non-LLDC ACP countries should be offered a series of regional and sub-regional free trade agreements. Not only would such arrangements seek to be WTO compatible, but the Commission also sees reciprocal regional agreements as stepping stones to fully liberalised trade and the integration of the developing countries into the world economy – an important development cooperation objective of the Maastricht Treaty.This article examines the Commission's proposals, and analyses the likely static and dynamic effects of a free trade agreement on the African ACP countries. It concludes by questioning whether the Commission's proposals would assist, rather than hinder, the regional integration and greater participation of these countries in the world economy.

ASEAN and the Regionalization and Globalization of World Trade

The three decades of ASEAN's life have coincided with powerful tendencies towards regionalization and globalization of economic activity. This article (I) discusses these worldwide tendencies and their implications for ASEAN; (2) compares the dynamics of trade expansion within ASEAN with those of the European Union and the North American Free Trade Agreement territories; (3) discusses ASEAN in the context of the Asia-Pacific Economic Co-operation forum, and (4) argues that ASEAN is a successful example of economically efficient regional co-operation to achieve trade expansion. I. A Successful Regional Group ASEAN was formed amongst five states three decades ago with mainly political objectives. This was a time of recent military conflict and considerable continuing tension amongst several of ASEAN's members. It was a time of political instability on the border of the original ASEAN, in particular with the war in Indochina. And it was a time of political uncertainty within several of the ASEAN members, as they sought a firm basis for development. The political objectives were met splendidly. Gradually, objectives of economic co-operation became more prominent in ASEAN - notably in a programme of special measures to promote internal trade expansion from 1976, and with the formation of the ASEAN Free Trade Area (AFTA) from 1992. The programmes to expand trade amongst ASEAN economies prior to the formation of AFTA were generally seen as having been unsuccessful. The complementation agreements and ASEAN industrial projects of the late 1970s did not amount to much. The ASEAN trade preferences did not bite deeply, and were overtaken by multilateral trade liberalization. It was common to point to relatively modest shares of intra-ASEAN in total trade (24 per cent in 1965, 24 per cent in 1995, and lower ratios in between) as evidence of the modest importance, or the unimportance, of the region to the economy of its members. This article sets out to demonstrate that this is a false perspective. Intra-ASEAN trade has grown more rapidly than trade within either of the major regional trading blocs over these past three decades. Intra-regional trade absorbs a higher proportion of the production of the ASEAN economies than of the members of the European Union (EU) or the signatories of the North American Free Trade Agreement (NAFTA). These powerful facts have been obscured by focus on another statistic - the share of intraregional trade in total trade. This focus counts as a failure what is in reality a great achievement of ASEAN: the maintenance of rapid growth in extra-regional, and especially intercontinental, trade alongside strong expansion from a high base of trade within ASEAN. ASEAN as a regional economic arrangement is an outstandingly successful example of open regionalism, or regional co-operation to promote regional trade without discrimination against outsiders. The three decades of ASEAN's life have coincided with powerful tendencies towards regionalization as well as globalization of economic activity. Section II of this article discusses these world-wide tendencies and their implications for ASEAN. Section III compares the dynamics of trade expansion within ASEAN with those of the EU and NAFTA. Section IV discusses ASEAN in the context of the Asia Pacific Economic Co-operation (APEC) forum, and argues that ASEAN is a successful example of economically efficient regional co-operation to achieve trade expansion. It raises a few questions about how the financial problems of 1997 might affect this success. II. Regionalization and Globalization The three decades of ASEAN's existence so far have seen rapid and inexorable increase in the role of international transactions in global economic activity. There has been a tendency towards acceleration of the internationalization of economic life, especially since the mid-1980s. This has been reflected in large increases in the ratio of international trade to GDP, and even more rapid increases in the ratio of international [trade] to total investment. …

Expatriate aid salaries in Malaŵi: A doubly demotivating influence?

Despite the rising cost of expatriate aid, we still know very little about its effectiveness, especially in sub-Saharan Africa. Education is a major objective of technical cooperation, and at the University of Malaŵi we surveyed both locally paid Malaŵian ( N = 29) and expatriate lecturers ( N = 29). Malaŵians emphatically agreed that aid salaries demotivated local lecturers, while the expatriates may have been resolving guilt about their greater pay by convincing themselves of their superiority, which could also result in their own demotivation. Aid salary differentials might therefore be demotivating both host and expatriate lecturers.

An ODP computational model of a cooperative binding object

A next generation of systems that should appear will have to manage simultaneously several geographically distributed users. These systems belong to the class of computer-supported cooperative work systems (CSCW). The development of such complex systems requires rigorous development methods and flexible open architectures. Open distributed processing (ODP) is a standardization effort that aims at providing such architectures. ODP features appropriate abstraction levels and a clear articulation between requirements, programming and infrastructure support. ODP advocates the use of formal methods for the specification of systems and components. The computational model, an object-based model, one of the abstraction levels identified within ODP, plays a central role in the global architecture. In this model, basic objects can be composed with communication and distribution abstractions (called binding objects) to form a computational specification of distributed systems, or applications. Computational specifications can then be mapped (in a mechanism akin to compilation) onto an engineering solution. We use an ODP-inspired method to computationally specify a cooperative system. We start from a general purpose component that we progressively refine into a collection of basic and binding objects. We focus on two issues of a co-authoring application, namely, dynamic reconfiguration and multiview synchronization. We discuss solutions for these issues and formalize them using the MT-LOTOS specification language that is currently studied in the ISO standardization formal description techniques group.

Synergistic modelling of tasks, users and systems using formal specification techniques

This paper aims at clarifying the articulation between the task models and system models encountered in CHI design practices. We demonstrate how the use of a formal task model may enhance the design of interactive systems, by providing quantitative results on which designers may base their decisions. We also demonstrate that it is possible to describe both task and system models within the same formal framework. This enables us firstly to formally prove that task and system models comply with each other, and secondly to perform quantitative analysis on the combination of task and system models. The approach is illustrated by a toy example which, despite its small size, allows us to develop both task and device models, and to perform several iterations of the design process. The device and tasks are modelled using the Interactive Cooperative Objects (ICO) formalism, which is based on Petri nets and on the object-oriented approach. The formality of Petri nets allows for axiomatic validation of isolated and interacting subsystems.

The Child-Adult Medical Procedure Interaction Scale-Revised: an assessment of validity.

Investigated the validity of the Child-Adult Medical Procedure Interaction Scale-Revised (CAMPIS-R) using multiple concurrent objective and subjective measures of child distress, approach-avoidance behavior, fear, pain, child cooperation, and parents' perceived ability to help their preschool children during routine immunizations. Parents', staffs', and children's behaviors in the treatment room were videotaped and coded. Results indicate that the validity of the CAMPIS-R codes of Child Coping and Distress, Parent Distress Promoting and Coping Promoting, and Staff Distress Promoting and Coping Promoting behavior were supported, with all significant correlations being in the predicted direction. An unanticipated finding was that the child, parent, and staff Neutral behaviors were inversely related to some measures of distress and positively related to some measures of coping. Interobserver reliability was high for each CAMPIS-R code.

Bclasses: A construct and method for modelling co-operative object behaviour

Current object-oriented (OO) modelling techniques emphasise the static aspects of data objects. Dynamics in general and collaborations between objects in particular tend to be poorly supported and are often treated separately. A full understanding of an object is hindered if we cannot easily grasp what it can do as well as what it is. We require a way of expressing collaborations. Our approach abstracts collaborations and suggests a method of integrating these abstractions into mainstream OO data definition languages (DDLs) thereby adding new modelling primitives. We argue that these are closer to real-world views of objects and are therefore more useful than the modelling contrivances in current use. We demonstrate how these primitives may be translated into DDLs which are easily mapped onto OO programming languages.

Cooperative Information Sharing: Developing a Shared Object Service

This paper examines the importance of sharing within cooperative systems and argues for a specialized service to support the cooperative aspects of information sharing. An investigation into the current information models used by Computer Supported Cooperative Work (CSCW) applications is presented. This is complemented by highlighting the problems faced by traditional database mechanisms in supporting cooperative applications. From this we form a set of requirements for CSCW information systems, and this analysis is used directly in the creation of new software concepts and an associated framework. Rather than present a detailed design, we propose a set of novel and viable design concepts, and the beginnings of an architectural framework for providing shared object services for CSCW systems. The relationship between the cooperative shared object service and existing services is briefly examined. A number of services of particular importance to CSCW systems are identified. More detailed consideration is given for a selection of service elements. The paper presents both the need for these services and the means of realizing the shared object service by augmenting existing object facilities.

Non-Linear Pricing Schemes for Co-Operatives: The Equity/Efficiency Trade-Off

Co-operatives are an important institution in North America, especially in the agri-food industry. Producer co-operatives control nearly 80 percent of grain handling, over 40 percent of dairy products manufacturing and about 30 percent of honey and maple syrup processing. A co-operative's main objective is to improve the well-being of its membership and in doing so it generally attempts to govern itself according to the principles set forth by the International Co-operative Alliance: open and voluntary membership; democratic control; limited return on equity; and return of surplus to members according to patronage. The economic benefit for the co-operative's membership primarily stems from the procompetitive effect that it provides within the industry. The standard monopoly/monopsony externality is generally not a problem with a co-operative because members have claims on the entire surplus generated by the organization. In many industries, processing co-operatives are capital intensive and thus operate with relatively high fixed costs and flat marginal cost schedules. In such cases, the transfer price between the co-operative and its members may be significantly less than the net selling price of the processed product because a relatively high fraction of the selling price is used to cover fixed costs. In other words, the co-operate will price off its net average revenue product (NARP) schedule rather than its value of marginal product (VMP) schedule and the former may lie significantly below the latter. Thus, even though the monopoly/monopsony externality may not be a problem with cooperative marketing, an efficiency loss in the form of sub-optimally low production can still result because of the fixed cost externality. The purpose of this paper is to examine the use of non-linear pricing as a way of dealing with the externality described above. Non-linear pricing is used in situations with analogous externalities (e.g., block rate pricing by

Distributed and cooperative object pushing by multiple mobile robots based on communication

This paper describes the implementation of distributed and cooperative object pushing by multiple mobile robots based on communication. In order to realize a multi-functional, flexible and robust r...

Book Reviews : Business objects: delivering cooperative objects for client-server Oliver Sims

Book Reviews : Business objects: delivering cooperative objects for client-server Oliver Sims

Vehicle Management System for Operating Multiple Vehicles

Multiple vehicle operation (e. g. cooperative object search) using autonomous underwater vehicles is an expected paradigm for deep ocean survey and exploration.In this paper, the system which consists of homogeneous vehicles is introduced to make a robust multiple vehicle system. The vehicle control architecture implemented in each member of the vehicles includes two decision making modules : one refers the individual environmental information gotten by its own sensors, and the other shares information received by other vehicles. By separating the decision maker into these two modules, the mission operator can easily write programs for each vehicle's behavior to generate an appropriate total vehicles' behavior. The performance of the vehicle's controlled by the proposed system is demonstrated on a multi-vehicle simulator, and the total behavior shows that the vehicles generate a formation which has not been explicitly given.