PROCASE: a case-based process planning system for machining of rotational parts

This paper introduces a case-based process planning system PROCASE which generates new process routines through learning from existing process routines. In contrast to traditional rule-based systems, the process planning knowledge of the PROCASE is represented in terms of cases instead of production rules. The planning basically comprises case retrieving and case adaptation rather than chaining applicable rules together to form process plans. The advantages are, first, the system is cheaper to build as it saves the expense of knowledge acquisition. Second, the system is able to advance its knowledge automatically through planning practice. Third, it is robust, because the reasoning is not based on pattern matching but similarity comparison. PROCASE has three modules: the retriever, the adapter and the simulator. It is supported by a feature-based representation scheme which naturally serves as the case indices for case retrieving and adaptation. The retriever uses a similarity metric to retrieve an old case which is the most similar case, among all old ones, to the new case. The adapter is then activated to adapt the process plan of the retrieved case to fit the needs for the new case. The simulator is used to verify the feasibility of the adapted plan. PROCASE is implemented on a Silicon Graphics IRIS workstation using C++ . An example is given to demonstrate how the process routine is generated by the system proposed by the authors.     

Theory of planning behavior (TPB) and customer satisfaction in the continued use of e-service: An integrated model

This study has devoted much effort to developing an integrated model designed to predict and explain an individual’s continued use of online services based on the concepts of the expectation disconfirmation model and the theory of planned behavior. Empirical data was collected from a field survey of Cyber University System (CUS) users to verify the fit of the hypothetical model. The measurement model indicates the theoretical constructs have adequate reliability and validity while the structured equation model is illustrated as having a high model fit for empirical data. Study’s findings show that a customer’s behavioral intention towards e-service continuance is mainly determined by customer satisfaction and additionally affected by perceived usefulness and subjective norm. Generally speaking, the integrated model can fully reflect the spirit of the expectation disconfirmation model and take advantage of planned behavior theory. After consideration of the impact of systemic features, personal characteristics, and social influence on customer behavior, the integrated model had a better explanatory advantage than other EDM-based models proposed in prior research.     

Optimization of machining processes from the perspective of energy consumption: A case study

One of the primary objectives of sustainable manufacturing is to minimize energy consumption in its manufacturing processes. A strategy of energy saving is to adapt new materials or new processes; but its implementation requires radical changes of the manufacturing system and usually a heavy initial investment. The other strategy is to optimize existing manufacturing processes from the perspective of energy saving. However, an explicit relational model between machining parameters and energy cost is required; while most of the works in this field treat the manufacturing processes as black or gray boxes. In this paper, analytical energy modeling for the explicit relations of machining parameters and energy consumption is investigated, and the modeling method is based on the kinematic and dynamic behaviors of chosen machine tools. The developed model is applied to optimize the machine setup for energy saving. A new parallel kinematic machine Exechon is used to demonstrate the procedure of energy modeling. The simulation results indicate that the optimization can result in 67% energy saving for the specific drilling operation of the given machine tool. This approach can be extended and applied to other machines to establish their energy models for sustainable manufacturing.     

六自由度检修机械臂合理路径规划系统设计

为减少六自由度检修机械臂抓取动作花费的时间,设计一种六自由度检修机械臂合理路径规划系统.此次研究的系统硬件部分主要包含主控制器、伺服电机控制器与通信模块.系统软件部分,计算出机器人与障碍物之间的距离,并计算出所有机器人上点与障碍物之间的距离,采用设置虚拟障碍物的创新型人工势场法进行路径规划,避免传统人工势场法的弊端,以...     

Agile product line planning: A collaborative approach and a case study

Agile methods and product line engineering (PLE) have both proven successful in increasing customer satisfaction and decreasing time to market under certain conditions. Key characteristics of agile methods are lean and highly iterative development with a strong emphasis on stakeholder involvement. PLE leverages reuse through systematic approaches such as variability modeling or product derivation. Integrating agile approaches with product line engineering is an interesting proposition which – not surprisingly – entails several challenges: Product lines (PL) rely on complex plans and models to ensure their long-term evolution while agile methods emphasize simplicity and short-term value-creation for customers. When incorporating agility in product line engineering, it is thus essential to define carefully how agile principles can support particular PLE processes. For instance, the processes of defining and setting up a product line (domain engineering) and deriving products (application engineering) differ significantly in practices and focus with implications on the suitability of agile principles. This paper presents practical experiences of adopting agile principles in product line planning (a domain engineering activity). ThinkLets, i.e., collaborative practices from the area of collaboration engineering, are the building blocks of the presented approach as they codify agile principles such as stakeholder involvement, rapid feedback, or value-based prioritization. We discuss how our approach balances agility and the intrinsic needs of product line planning. A case study carried out with an industrial partner indicates that the approach is practicable, usable, and useful.     

Recent development in CNC machining of freeform surfaces: A state-of-the-art review

Freeform surfaces, also called sculptured surfaces, have been widely used in various engineering applications. Freeform surfaces are primarily manufactured by CNC machining, especially 5-axis CNC machining. Various methodologies and computer tools have been developed in the past to improve efficiency and quality of freeform surface machining. This paper aims at providing a state-of-the-art review on recent research development in CNC machining of freeform surfaces. This review primarily focuses on three aspects in freeform surface machining: tool path generation, tool orientation identification, and tool geometry selection. For each aspect, first concepts, requirements and fundamental research methods are briefly introduced. The major research methodologies developed in the past decade in each aspect are presented with details. Problems and future research directions are also discussed.     

Managing the full ERP life-cycle: Considerations of maintenance and support requirements and IT governance practice as integral elements of the formula for successful ERP adoption

Companies adopting enterprise resource planning (ERP) systems have often focused primarily on implementation-related factors while neglecting those of post-implementation. As a result, the usefulness and operation of the ERP systems, once installed, are compromised. This research adopted a case study approach to demonstrate that ERP adoption efforts that fail to pay attention to post-implementation requirements (especially those relevant to maintenance and support (M&S)) from an early stage in the project lifecycle will face dire consequences. It points out that poor planning and management of M&S services can imperil the normal operations of an ERP system and the daily activities of a business. With the life span of ERP systems getting shorter, sound M&S practices can extend their life and create a stable system platform to support efficient and effective business operations. M&S issues deserve to be considered as integral elements among the critical success factors (CSF) of ERP adoption projects. In other words, ERP success requires a full lifecycle perspective to be taken by adopting companies. With lessons having been learned from the mistakes in the first project, the company in this case study revamped its ERP implementation second time out, with due consideration being given to M&S strategies and practices from project initiation onward in order to realize a stable, usable, and maintainable system. The case study explores and identifies the critical success factors (CSF) of ERP adoption, and shows that M&S must be included as a key element from the outset and throughout the system lifecycle. Our findings capture a great deal of experience for any ERP adopting companies to follow in order to avoid learning costly lessons both in implementation and subsequent M&S throughout the lifespan of the system. A set of propositions is also presented for academic researcher to consider in future ERP research endeavors.     

Nicolog: A simple yet powerful cc(FD) language

In this paper, we describe Nicolog, a language with capabilities similar to recently developed constraint logic programming (CLP) languages such as CLP(BNR), clp(FD), and cc(FD). Central to Nicolog are projection constraints (PCs), a sublanguage for compiling and optimizing constraint propagation in numeric and Boolean domains. PCs are an interesting generalization of the indexical constraints introduced in cc(FD) and also found in clp(FD). Nicolog compiles a very general class of built-in constraints into equivalent sets of PCs, allowing an arbitrary mixture of integer (easily extensible to real) and Boolean operations. Nicolog also lets the user program PCs directly, making it possible to implement new sophisticated propagation procedures. We show that PCs are a simple, efficient, and flexible way to implement most of the propagation procedures possible in other FD CLP systems. These include procedures for cardinality, constructive disjunction, implication, and mixed Boolean/numeric constraints. Empirical results with a simple prototype Nicolog implementation based on the WAM architecture show it can solve hard problems with speed comparable to the fastest existing CLP systems.     

Playful public participation in urban planning: A case study for online serious games

The aim of this paper is to study the implementation of online games to encourage public participation in urban planning. Its theoretical foundations are based on previous work in public participatory geographical information systems (PP GISs), play and games, with a special focus on serious games. Serious games aim to support learning processes in a new, more playful way. We developed the concept of playful public participation in urban planning, including playful elements such as storytelling, walking and moving, sketching, drawing, and games. A group of students designed an online serious public participatory game entitled NextCampus. The case study used in NextCampus was taken from the real-world question of a possible move of a university campus to a new location in the city of Hamburg, Germany. The development of the serious public participatory game NextCampus resulted in a physical prototype, user interface design, and a computational model of the game. The NextCampus game was tested with the help of two groups of urban planning students and presented to three external experts who provided valuable recommendations for further development. The critical comments questioned the level of complexity involved in such games. The positive comments included recognition of the potential for joy and the playfulness a game like NextCampus could evoke.     

A contribution to the development of strategic control and planning instruments: An acquisition case study

The present paper is part of the efforts made by the authors in recent years to develop strategic control and planning instruments in corporations using OR‐techniques like system dynamics, control theory, and group multicriteria decision aid. A more general framework called ‘adaptive control methodology’ (ACM) combines all these techniques. It has been presented in several papers. The objective of the present analysis is to calibrate this instrument and to tune it to the corporate needs by analysing real‐world applications. More specifically, several case studies have been investigated in large multinational organisations in the food sector. An acquisition case has been used for the calibration purpose. It is analysed in the paper from the ACM perspective to provide additional material for revisiting and improving the methodology.     

Identifying competences for the design of systems supporting complex decision-making tasks: a managerial planning application

The work presented in this paper is addressed to the front-end phases of the development of a system supporting a complex decision-making task: high-level managerial planning in small-to-medium enterprises (SMEs). It attempts to identify characteristics of the competences possessed by experienced managers and used when taking high-level managerial planning decisions, and to assess their potential implications for system design. The work is based on the assumption that the design of effective systems supporting complex decision-making tasks in a specific domain, would require elicitation of competences possessed by experienced persons in the domain, especially those related to the mental processes followed when confronting the cognitive constraints involved in the specific decision-making environment. Such an investigation would lead to the development of systems improving decision making since they would (1) respond to the difficulties met by potential users in performing complex decision-making tasks; (2) reduce possible negative consequences of users' decision-making competences; and (3) at the same time they would achieve the required compatibility with users' mental processes. The research methodology was based on a planning scenario and on an analysis of verbal protocols obtained from a sample of small-enterprise managers confronted with this scenario. Results provide evidence about (1) the type of decisions and actions taken by experienced managers when confronted with the cognitive constraints involved in managerial planning situations; (2) phases and sequence of the process of arriving at planning decisions; and (3) data used and types of analyses performed. Some general implications are drawn from these results with respect to the configuration of a system aiming at supporting managerial planning. These refer to the type of support to be provided at various phases of the planning process, possible features of the human-computer interface, and generic or task/user specific aspects of the system.     

A case study on applying formal methods to medical devices: computer-aided resuscitation algorithm

The design and functional complexity of medical devices have increased during the past 50 years, evolving from the use of a metronome circuit for the initial cardiac pacemaker to functions that include electrocardiogram analysis, laser surgery, and intravenous delivery systems that adjust dosage based on patient feedback. As device functionality becomes more intricate, concerns arise regarding efficacy, safety, and reliability. It thus becomes imperative to adopt a standard or methodology to ensure that the possibility of any defect or malfunction in these devices is minimized. It is with these facts in view that regulatory bodies are interested in investigating mechanisms to certify safety-crictical medical devices. These organizations advocate the use of formal methods techniques to evaluate safety-critical medical systems. However, the use of formal methods is keenly debated, with most manufacturers claiming that they are arduous and time consuming.In this paper we describe our experience in analyzing the requirements documents for the computer-aided resuscitation algorithm (CARA) designed by the Resuscitative Unit of the Walter Reed Army Institute of Research (WRAIR). We present our observations from two different angles – that of a nonbeliever in formal methods and that of a practitioner of formal methods. For the former we catalog the effort required by a novice user of formal methods tools to carry out an analysis of the requirements documents. For the latter we address issues related to choice of designs, errors in discovered requirements, and the tool support available for analyzing requirements .     

Dynamic scheduling of maintenance tasks in the petroleum industry: A reinforcement approach

Petroleum industry production systems are highly automatized. Maintenance of such systems is vital, not only to maintain production efficiency but also to insure minimal safety levels. Maintenance task scheduling is difficult since some tasks are already identified because they must be done repeatedly, and other tasks need to be identified dynamically. In this paper, we present a multi-agent approach for the dynamic maintenance task scheduling for a petroleum industry production system. Agents simultaneously insure effective maintenance scheduling and the continuous improvement of the solution quality by means of reinforcement learning, using the SARSA algorithm. Reinforcement learning allows the agents to adapt, learning the best behaviors for their various roles without reducing the performance or reactivity. To demonstrate the innovation of our approach, we include a computer simulation of our model and the results of experimentation applying our model to an Algerian petroleum refinery.     

Integration of process planning and scheduling—A modified genetic algorithm-based approach

Traditionally, process planning and scheduling for parts were carried out in a sequential way, where scheduling was done after process plans had been generated. Considering the fact that the two functions are usually complementary, it is necessary to integrate them more tightly so that performance of a manufacturing system can be improved greatly. In this paper, a new integration model and a modified genetic algorithm-based approach have been developed to facilitate the integration and optimization of the two functions. In the model, process planning and scheduling functions are carried out simultaneously. In order to improve the optimized performance of the modified genetic algorithm-based approach, more efficient genetic representations and operator schemes have been developed. Experimental studies have been conducted and the comparisons have been made between this approach and others to indicate the superiority and adaptability of this method. The experimental results show that the proposed approach is a promising and very effective method for the integration of process planning and scheduling.     

A note on some collapse results of valued constraints

Valued constraint satisfaction problem (VCSP) is an optimisation framework originally coming from Artificial Intelligence and generalising the classical constraint satisfaction problem (CSP). The VCSP is powerful enough to describe many important classes of problems. In order to investigate the complexity and expressive power of valued constraints, a number of algebraic tools have been developed in the literature. In this note we present alternative proofs of some known results without using the algebraic approach, but by representing valued constraints explicitly by combinations of other valued constraints.     

A dynamic priority based path planning for cooperation of multiple mobile robots in formation forming

Robots that work in a proper formation show several advantages compared to a single complex robot, such as a reduced cost, robustness, efficiency and improved performance. Existing researches focused on the method of keeping the formation shape during the motion, but usually neglect collision constraints or assume a simplified model of obstacles. This paper investigates the path planning of forming a target robot formation in a clutter environment containing unknown obstacles. The contribution lies in proposing an efficient path planner for the multiple mobile robots to achieve their goals through the clutter environment and developing a dynamic priority strategy for cooperation of robots in forming the target formation. A multirobot system is set up to verify the proposed method of robot path planning. Simulations and experiments results demonstrate that the proposed method can successfully address the collision avoidance problem as well as the formation forming problem.     

Automated instructional design for CSCL: A hierarchical task network planning approach

In Computer Supported Collaborative Learning (CSCL), one of the most important tasks for instructional designers is to define scenarios that foster group learning. Such scenarios, defined as Units of Learning (UoLs), comprise different components and are organized according to pedagogical approaches to orchestrate group learning processes. Examples of UoL components are learning objects, student roles, student characteristics (e.g., background, preferences, learning styles, etc.), instructional/learning goals, and activities, among others. Thus, the instructional design (ID) of a proper UoL for CSCL is a complex task that requires practice and experience. This is particularly true when designing, developing, adapting, and customizing UoLs, taking into consideration different instructional/learning goals and individual preferences of students. This paper therefore proposes using a Hierarchical Task Network (HTN) planning approach to automate and optimize the tasks of designers. To accomplish that, we define an initial CSCL scenario as “an ID task” and “a set of information related to students and the domain to be taught.” Then we propose a model that formally describes ID for CSCL as HTN planning, where the initial CSCL scenario is adapted and refined according to student needs. In this model, the ID strategies are defined as hierarchical tasks and methods into a planning domain definition, and the initial CSCL scenario is defined as a planning problem definition. To validate our approach, we develop a CSCL courseware generator that (i) helps designers to set up an initial CSCL scenario; (ii) automatically generates a personalized UoL based on a given initial scenario; and (iii) supports the adaptation of UoLs.