On controllability and control laws for discrete linear repetitive processes

Repetitive processes are a distinct class of 2D systems (i.e. information propagation in two independent directions) of both systems theoretic and applications interest. They cannot be controlled by the direct extension of existing techniques from either standard (termed 1D here) or 2D systems theory. This article develops significant new results on the relationships between one physically motivated concept of controllability for the so-called discrete linear repetitive processes and the structure and design of control laws, including the case when disturbances are present.     

Relaxed pass profile controllability of discrete linear repetitive processes

Repetitive processes are a distinct class of 2D systems (i.e. information propagation in two independent directions) of both systems theoretic and applications interest. They cannot be controlled by direct extension of existing techniques from either standard (termed 1D here) or 2D systems theory. In this paper we develop significant new results on controllability of so-called discrete linear repetitive processes. The end result is necessary and sufficient conditions for this property in terms of matrix rank based tests. The application of these tests is illustrated by a numerical example.     

Output feedback control of discrete linear repetitive processes

Repetitive processes are a distinct class of 2D systems (i.e. information propagation in two independent directions) of both systems theoretic and applications interest. They cannot be controlled by direct extension of existing techniques from either standard (termed 1D here) or 2D systems theory. Here, we give new results on the relatively open problem of the design of physically based control laws using an LMI setting. These results are for the sub-class of the so-called discrete linear repetitive processes which arise in applications areas such as iterative learning control.     

Iterative learning control — 2D control systems from theory to application

It has long been recognized that iterative learning control is a 2D system, i.e. information propagation occurs in two independent directions. In this paper, the application of so-called norm optimal iterative learning control, which has its origins in the theory of the class of 2D systems known as linear repetitive processes to an experimental testbed in the form of a chain conveyor system is reported. This includes the motivation for applying iterative learning control to such systems, the design and construction of the testbed, and its use to demonstrate that norm optimal iterative learning control gives superior performance over alternatives. As such, it provides an application for 2D systems theory where distinct advantages arise from using such a setting for modelling and control.     

Semantic business process integration based on ontology alignment

Innovation and agility should be provided to businesses by efficient collaboration (i.e., communication and sharing) between them. However, semantic heterogeneity between business processes is a serious problem for automatically supporting cooperation processes (e.g., knowledge sharing and querying-based interactions) between businesses. In order to overcome this problem, we propose a novel framework based on aligning business ontologies for integrating heterogeneous business processes. We can consider two types of alignment processes; (i) manual alignment for building a whole business process ontology in a business process management (BPM) system and (ii) automated alignment between business processes of different BPM systems. Thereby, the optimal integration between two business processes has to be discovered to maximize the summation of a set of partial similarities between semantic components consisting of the business processes. In particular, the semantic component are extracted from semantic annotations of business processes. For evaluating the proposed system, we have conducted experimentations by using 22 business process management systems, which are organized as six business alliances. We have assumed that business processes in a same BPM system should be built with a common ontologies. The proposed alignment method has shown about 71.3% of precision (65.4% of recall). In addition, we found out that alignment results are dependent on some characteristics of ontologies (e.g., depth and number of classes).     

Development of an environmental virtual field laboratory

Laboratory exercises, field observations and field trips are a fundamental part of many earth science and environmental science courses. Field observations and field trips can be constrained because of distance, time, expense, scale, safety, or complexity of real-world environments. Our objectives were to develop an environmental virtual field laboratory to study environmental properties and processes that stimulate the higher-order cognitive skills of students. We considered the following criteria for our virtual field laboratory: (i) global access, i.e., web-based implementation; (ii) simulation of a variety of learning mechanisms; (iii) interactivity to engage students; (iv) compartmentalization and hierarchical organizational structure; (v) abstraction of 2D and 3D geographic objects (e.g. soils, terrain) and dynamic ecosystem processes (e.g. water flow) using geostatistics and scientific visualization techniques. Cognitive science was considered during the design of our computer-aided instructional tools to enhance the effectiveness for learning. Our virtual field laboratory mimicked the students' learning processes that operate during real field trips and/or field observations; and provided students with a simulation environment to study environmental processes in space and time that cannot be provided on a real field trip. We implemented the following learning mechanisms: (i) exploration-based learning; (ii) analogy-based learning; (iii) science inquiry learning; (iv) abstraction-based learning. To engage students in our environmental virtual field laboratory, we implemented multiple interactivity functions including the exploration of 3D models and adaptive selective simulations. We used Virtual Reality Modeling Language, Java, Java Script, and External Authoring Interface to develop the environmental virtual field laboratory for a 42-ha flatwood site in Florida for which extensive datasets existed. Our digital learning environment offers potential to enhance existing on-campus courses and/or distance education courses.     

Consistency constraints and 3D building reconstruction

Virtual architectural (indoor) scenes are often modeled in 3D for various types of simulation systems. For instance, some authors propose methods dedicated to lighting, heat transfer, acoustic or radio-wave propagation simulations. These methods rely in most cases on a volumetric representation of the environment, with adjacency and incidence relationships. Unfortunately, many buildings data are only given by 2D plans and the 3D needs varies from one application to another. To face these problems, we propose a formal representation of consistency constraints dedicated to building interiors and associated with a topological model. We show that such a representation can be used for: (i) reconstructing 3D models from 2D architectural plans (ii) detecting automatically geometrical, topological and semantical inconsistencies (iii) designing automatic and semi-automatic operations to correct and enrich a 2D plan. All our constraints are homogeneously defined in 2D and 3D, implemented with generalized maps and used in modeling operations. We explain how this model can be successfully used for lighting and radio-wave propagation simulations.     

Behaviours of concurrent systems

Concurrent systems and their behaviours are investigated. The behaviour of a system is understood as the set of processes which the system is capable to realize. The processes may be elementary (indivisible) or may consist of some components. Two ways of composing processes are considered: sequentially (one component is a continuation of another) and in parallel (the components are concurrent, i.e. independent).The behaviour of a system is defined as a set of processes which can be obtained by composing certain elementary processes. All information on the existing independence is reflected so that the system is completely determined by its behaviour.It is explained which sets of processes are the behaviours of concurrent systems.     

Business alignment: using process mining as a tool for Delta analysis and conformance testing

Increasingly, business processes are being controlled and/or monitored by information systems. As a result, many business processes leave their “footprints” in transactional information systems, i.e., business events are recorded in so-called event logs. Process mining aims at improving this by providing techniques and tools for discovering process, control, data, organizational, and social structures from event logs, i.e., the basic idea of process mining is to diagnose business processes by mining event logs for knowledge. In this paper we focus on the potential use of process mining for measuring business alignment, i.e., comparing the real behavior of an information system or its users with the intended or expected behavior. We identify two ways to create and/or maintain the fit between business processes and supporting information systems: Delta analysis and conformance testing. Delta analysis compares the discovered model (i.e., an abstraction derived from the actual process) with some predefined processes model (e.g., the workflow model or reference model used to configure the system). Conformance testing attempts to quantify the “fit” between the event log and some predefined processes model. In this paper, we show that Delta analysis and conformance testing can be used to analyze business alignment as long as the actual events are logged and users have some control over the process.

新的二维形状描述方法与边界平滑*

提出了一种新的二维形状描述方法,该方法利用对目标图像边界搜索的结果,将目标边界曲线像素的坐标（xi,yi）分别用两个数组x =X［i］;y=Y［i］描述。将一个二维图像的问题转换成两个一维数组的分析问题,简化了分析的复杂度。通过分别对两个数组的处理可以对原目标边界进行一系列处理,如边界圆滑、锐化、拐点检测等。介绍了该描述方法及其基本性质,并利用该描述方法通过小波分解对工件目标边界的平滑进行了具体分析。     

Supervisory control for deadlock avoidance in compound processes

Most of the research devoted to the supervisory control for deadlock avoidance in automated manufacturing systems has employed various models that represent concurrent sequential processes. In this paper, we address this problem for compound processes, that is, sequences of operations related in the fork/join manner and interacting as consumers/producers. The abstraction is used to model the flow of materials where independently processed components can be joined together and undergo further processing as a whole (e.g., to make an assembly or for a common transport), or material units can be split up so that their components will follow separate routes (e.g., at disassembly or separate processing of parts delivered in magazines), as well as to model the flow of objects that require a temporary meeting (e.g., independently routed pallets with the base components and pallets with parts to be mounted onto the base). Each process is represented with a marked graph, and the dynamics of the system are restricted with a feasibility function ensuring the feasible access to the shared resources. Unlike in sequential processes, in the class considered here, not all processes are realizable, i.e., possess a deadlock-free execution sequence. We prove that the problem of the distinction between realizable and unrealizable systems is NP-complete (thus intractable in practice) and propose a constraint that in a sufficient way allows us to distinguish a subclass of realizable compound processes. It is shown that the optimal, i.e., the minimally restrictive, supervisory control for this subclass of processes also poses an NP-hard problem. Therefore, we propose a compromise solution: a more restrictive, yet computationally acceptable admissibility function for guarding the event occurrence. The correctness of the control is proved formally by demonstrating the liveness and reversibility of the resulting model.     

Search intensity versus search diversity: a false trade off?

An implicit tenet of modern search heuristics is that there is a mutually exclusive balance between two desirable goals: search diversity (or distribution), i.e., search through a maximum number of distinct areas, and, search intensity, i.e., a maximum search exploitation within each specific area. We claim that the hypothesis that these goals are mutually exclusive is false in parallel systems. We argue that it is possible to devise methods that exhibit high search intensity and high search diversity during the whole algorithmic execution. It is considered how distance metrics, i.e., functions for measuring diversity (given by the minimum number of local search steps between two solutions) and coordination policies, i.e., mechanisms for directing and redirecting search processes based on the information acquired by the distance metrics, can be used together to integrate a framework for the development of advanced collective search methods that present such desiderata of search intensity and search diversity under simultaneous coexistence. The presented model also avoids the undesirable occurrence of a problem we refer to as the ‘ergometric bike phenomenon’. Finally, this work is one of the very few analysis accomplished on a level of meta-meta-heuristics, because all arguments are independent of specific problems handled (such as scheduling, planning, etc.), of specific solution methods (such as genetic algorithms, simulated annealing, tabu search, etc.) and of specific neighborhood or genetic operators (2-opt, crossover, etc.).     

Control Issues in High-speed AFM for Biological Applications: Collagen Imaging Example

This article considers the precision positioning problem associated with high-speed operation of the Atomic Force Microscope (AFM), and presents an inversion-based control approach to achieve precision positioning. Although AFMs have high (nanoscale) spatial resolution, a problem with current AFM systems is that they have low temporal resolution, i.e., AFM imaging is slow. In particular, current AFM imaging cannot be used to provide three-dimensional, time-lapse images of fast processes when imaging relatively-large, soft samples. For instance, current AFM imaging of living cells takes 1-2 minutes (per image frame) - such imaging speeds are too slow to study rapid biological processes that occur in seconds, e.g., to investigate the rapid movement of cells or the fast dehydration and denaturation of collagen. This inability, to rapidly image fast biological processes, motivates our current research to increase the operating speed of the AFM. We apply an inversion-based feedback/feedforward control approach to overcome positioning problems that limit the operating speed of current AFM systems. The efficacy of the method, to achieve high-speed AFM operation, is experimentally evaluated by applying it to image collagen samples.     

Dynamic simulation of action at operations level

The attempt of using lumped or agent-based simulation models to support operations management in production systems puts action modelling to the fore. To fill the gap of classical decision-support systems ignoring human agents’ practices, a modelling framework of action at operations level is proposed. This framework aims at answering two questions: How to represent action? How to represent the management of action? Every action (i.e., what is actually done by an agent) is represented by a binary function of time governed by events detected upon processes of various kinds: artefacts (clocks or schedules), external processes occurring in the environment, other actions. In turn, every action exerts its effect on target processes. This modelling framework allows one to simulate the interpretation of ongoing actions by using temporal or propositional logics and operations management behaviors through plan specification and execution, action composition, and resource allocation to concurrent actions. It enables complex activity systems to be represented and management options to be tested by simulation. These capacities are illustrated on the example of a farming system. The main benefits and issues raised by this dynamical system approach close to the ‘situated’ (vs. ‘planned’) action paradigm are discussed in the light of related works in Artificial intelligence. Future directions of research are drawn, namely that of how to scale up this lower-level representation of action to the higher-level representation of agents endowed with skills relevant at the level of the individual (e.g., anticipation).     

Filling Out the Gaps: A Padding Algorithm for Transforming Out Timing Leaks

It has been shown that secret information can be leaked to external observers through covert timing channels. In this paper we are concerned with a kind of timing attack that wants to differentiate two processes, presented as probabilistic transition systems, by observing their timing behaviour. Our goal is to make the processes indistinguishable i.e. bisimilar, by adding virtual (dummy) states and transitions to the original processes (padding). Instead of padding the processes with whole virtual copies of their counterparts - as done by some padding algorithms - we present an algorithm that uses the bisimulation equivalence relation - computed as a lumping partition - as the main criterion to optimise the padding procedure.     

A numerical modelling of voltammetric reduction of substituted iodobenzenes reaction series. A relationship between reductions in the consecutive-mode multistep system and a multicomponent system. Determination of the potential variation of the elementary charge transfer coefficient

The cyclic voltammetry reduction process of the reaction series of substituted iodobenzenes X-C6H4-I where X = H, p-Cl, p-Br, p-I, p-CH3, m-CF3 was investigated in 0.3 M TBAP in DMF. A numerical model of the process consistent with the ECE mechanism of mono-iodobenzenes reduction and consecutive ECE-ECE reduction of p-diiodobenzene was applied. On the basis of alpha(i) vs. E(p,i) dependence, the value of delta a(i)/delta E was found to be 0.37 +/- 0.07 for first electron transfer (Eq. (10)). The ECE-ECE system seems to be an another example of elementary alpha kinetic discrimination between two identical two-electron processes analogous to that described in a previous paper (Sanecki, P., Kaczmarski, K. (1999). J. Electroanal. Chem. 471, 14 and erratum to it (2001)). A method of simultaneous treatment of the substrate and all electroactive intermediates, i.e. the transformation of any experimental consecutive CV reduction curves (e.g. ECE or ECE-ECE) into curves corresponding to reduction of the multi-component systems is presented and discussed.     

Combining fuzzy cognitive maps with agent-based modeling: Frameworks and pitfalls of a powerful hybrid modeling approach to understand human-environment interactions

Agent-based modeling (ABM) is an established technique to capture human-environment interactions in socio-ecological systems. As a micro-model, it explicitly represents each agent, such that heterogeneous decision-making processes (e.g. based on the beliefs and experiences of stakeholders) can anticipate the socio-environmental consequences of aggregated individual behaviors. In contrast to ABM, Fuzzy Cognitive Mapping takes a macro-level view of the world that represents causal connections between concepts rather than individual entities. Researchers have expressed interest in reconciling the two, i.e. taking a hybrid approach and drawing of the strengths of each to more accurately model socio-ecological interactions. The intuition is to take FCMs, which can be quickly developed using participatory modeling tools and use them to create a virtual population of agents with sophisticated decision-making processes. In this paper, we detail two ways in which this combination can be done, and highlight the key questions that modelers need to be mindful of.     

Average dwell time-based optimal iterative learning control for multi-phase batch processes

Multi-phase batch process plays an important role in modern industry, especially for processes with different dimensional phases. As the different phases may interact with each others deeply, when and how to perform the transfer between adjacent phases highly affect the control performance and product quality. Meanwhile, the running time in different phases influence the production efficiency. Therefore it is of crucial importance to study the control of multi-phase batch processes with time constraints. Take the injection molding process as an example, a multi-phase batch process can be regarded as a switched system with different-dimensional subsystems in each batch. In this paper, the multi-phase batch process is converted to an equivalent two-dimensional (2D) switched system and the repetitive and 2D nature of batch processes is explored. Within the framework of 2D system theory, both the exponential stability and the shortest running time are considered. Meanwhile, a compound 2D controller with optimal performance is designed. The contributions of this paper are as follows: (1) the batch process studied is with different dimensions in each phase. (2) using the average dwell time method, a sufficient condition ensuring the exponential stability is obtained, meanwhile, the minimum running time of each subsystem, i.e., the running time of each phase can be calculated. Finally, the proposed method is illustrated with an injection molding process to show the effectiveness.