Inferential control of product quality attributes—application to food cooking extrusion process

Reducing product quality variability is one of the most important issues for the process industry. As product quality attributes (PQAs) are often measured in a laboratory using off-line sensors, direct feedback control is not feasible unless expensive on-line sensors are used. Inferential control provides a means to the solution of this type of problem without the cost of expensive sensors. This paper reports a successful application of control of product quality attributes in a food cooking extruder. It covers the essential steps in achieving the control objective: (1) identifying the influential variables that can be measured on-line and have significant impact on the product quality attributes; (2) estimating a dynamic model between the influential variables and the PQAs for on-line prediction of product quality; (3) on-line feedback control using the influential variables. Experimental results demonstrate that the designed control system not only maintains the quality of the products but also automatically brings the PQAs to user's specification.     

On-Line Construction of Two-Dimensional Suffix Trees in O(n<Superscript>2</Superscript> log n) Time

The two-dimensional suffix tree of an n × n square matrix A is a compacted trie that represents all square submatrices of A[11]. For the off-line case, i.e., A is given in advance to the algorithm, it is known how to build it in optimal time, for any type of alphabet size [11],[18]. Motivated by applications in Image Compression[22[, Giancarlo and Guaiana [14] considered the on-line version of the two-dimensional suffix tree and presented an O(n² log² n)-time algorithm, which we refer to as GG. That algorithm is a nontrivial generalization of Ukkonen's on-line algorithm for standard suffix trees [23]. The main contribution in this paper is an O(log n) factor improvement in the time complexity of the GG algorithm, making it optimal for unbounded alphabets [9]. Moreover, the ideas presented here also lead to a major simplification of the GG algorithm. Technically, we are able to preserve most of the structure of the original GG algorithm, by reducing a computational bottleneck to a primitive operation, i.e., comparison of Lcharacters, which is here implemented in constant time rather than O(log n) time as in GG. However, preserving that structure comes at a price. Indeed, in order to make everything work, we need a careful reorganization of another fundamental algorithm: Weiner's algorithm for the construction of standard suffix trees [24]. Specifically, here we provide a version of that algorithm which takes linear time and works on-line and concurrently over a set of strings.     

Parameter ranking by orthogonalization—Applied to nonlinear mechanistic models

The paper addresses methods for parameter sensitivity analysis in a large, nonlinear, mechanistic model which is to be run in an on-line estimation scheme. The parameter sensitivity has been obtained by numeric approximation. The paper proposes and applies successive orthogonalization of the sensitivity derivative for parameter ranking. The method is easy to implement and the results are easily interpreted. Orthogonalization of the sensitivity matrix gives a triangular form of the squared sensitivity. The paper shows how the triangular form of the sensitivity derivative gives a particularly easy form of the variance contribution of individual parameters, provided the model error can be assumed Gaussian. This information has been used to decide how many parameters from the ranked set are to be selected for on-line estimation.     

A practical robust control scheme for yeast fed-batch cultures – An experimental validation

Model-based control of bioprocess is a difficult task due to the challenges associated with bioprocess modeling and the lack of on-line measurements. In this study, a robust controller using minimal process knowledge and minimal measurement information is developed and applied to the ethanol regulation in cultures of Saccharomyces cerevisiae. A Youla parametrization is selected in order to reject the disturbance associated to the substrate demand for cell growth and to robustify the control scheme to unstructured uncertainties and measurement noise. The performance of this control scheme is illustrated in simulation and with real on-line experimental data.     

Knowing when not to use the Internet: Shyness and adolescents’ on-line and off-line interactions with friends

The goal of the study was to explore the content of on-line and off-line peer interactions among shy and non-shy adolescents. Participants were 148 ten-to-eighteen year old adolescents in Rome, Italy (n = 98) and Ottawa, Canada (n = 50). Participants completed self reports of shyness and loneliness and web logs of their interactions with friends both in person and on-line. Among the results, there was little general difference in the general content and emotion expressed during the two modalities of interaction with friends, both of which were used in a wide variety of ways. Importantly, shy participants used the on-line modality more extensively than their non-shy counterparts to express negative emotions and to convey content regarding negative exchanges with peers. Such use of electronic communication may be an important contributor to their loneliness.     

Schools in contact; Electronic mail— myth or reality?

A variety of services, including Dialcom, BTGold, Prestel Mailbox, JANET and TTNS offering one-to-one to many communication services between educational and other institutions, have been in the market place for a considerable time, in some cases over 10 years. Schools have been slow to exploit the range of facilities available. A number of factors have inhibited growth, not least those of cost. Hertfordshire Local Education Authority has been in the forefront of pioneering on-line services between its schools and colleges and is now fully committed to both an integrated electronic mail service and a wide provision on on-line search facilities such as NERIS and PROFILE. The developments have, in the main, been curriculum led. Monitoring and assessing the quality of the communication between pupils, class groups and teachers, can prove difficult as the medium offers mainly a transient environment. This barrier to researching the effect that electronic mail has on human communication has been overcome to some extent by using the system itself to record a number of features concerning messages, e.g. length, time sent etc. In addition, the contents and styles of messaging are being observed by random sampling at a number of stations in educational institutions. In addition to reporting on this routine activity, the author will give account of a number of specific projects currently active including collaborative creative writing, Chatline for children with special needs and school twinning with other European countries, the Commonwealth and the U.S.A.     

A Hierarchical Extension of the <Emphasis Type="Italic">D</Emphasis><Superscript>*</Superscript> Algorithm

In this paper a contribution to the practice of path planning using a new hierarchical extension of the D^* algorithm is introduced. A hierarchical graph is stratified into several abstraction levels and used to model environments for path planning. The hierarchical D^* algorithm uses a down-top strategy and a set of pre-calculated trajectories in order to improve performance. This allows optimality and specially lower computational time. It is experimentally proved how hierarchical search algorithms and on-line path planning algorithms based on topological abstractions can be combined successfully.     

On-line diagnosis and uncertainty management using evidence theory––experimental illustration to anaerobic digestion processes

The on-line diagnosis is a key requirement in biological processes. This is particularly true in the case of wastewater treatment processes due to the composition of media, the requirements of operating conditions and the wide variety of possible disturbances that necessitate careful and constant monitoring of the processes. Moreover, because only partial information is available in an on-line context and because of the technical and biological complexities of the involved processes, specific characteristics are required for diagnosis purposes. Several approaches like quantitative model based, qualitative model based and process history based methods were applied over the years. This paper present a methodological framework based on evidence theory to manage the fault signals generated by conventional approaches (i.e., residuals from hardware and software redundancies, fuzzy logic based modules for process state assessment) and to account for uncertainty. The advantages of using evidence theory like modularity, detection of conflict and doubt in the information sources are illustrated with experimental results from a 1 m³ fixed bed anaerobic digestion process used for the treatment of industrial distillery wastewater.     

On-line implementation of a nonlinear distributed observer for a multizone furnace — comparative study with a nonlinear filter

The dynamic behavior of an experimental multizone electrical furnace is described by nonlinear partial differential equations. On this basis, a nonlinear distributed observer of the load temperature profiles is designed. The resulting observer equations are discretized by orthogonal collocation on finite elements and implemented on-line on a PC. The observer shows very good properties: easy tuning, robustness and small computer resources. Some experimental results and computer simulations are presented and discussed. Moreover, a comparison is performed between the observer and a distributed extended Kalman filter, including on-line performances and computational implementation aspects. It is shown that the observer requires less computational effort for similar performances.     

On-line trust: concepts, evolving themes, a model

Trust is emerging as a key element of success in the on-line environment. Although considerable research on trust in the offline world has been performed, to date empirical study of on-line trust has been limited. This paper examines on-line trust, specifically trust between people and informational or transactional websites. It begins by analysing the definitions of trust in previous offline and on-line research. The relevant dimensions of trust for an on-line context are identified, and a definition of trust between people and informational or transactional websites is presented. We then turn to an examination of the causes of on-line trust. Relevant findings in the human–computer interaction literature are identified. A model of on-line trust between users and websites is presented. The model identifies three perceptual factors that impact on-line trust: perception of credibility, ease of use and risk. The model is discussed in detail and suggestions for future applications of the model are presented.     

On-Line Resource Management with Application to Routing and Scheduling

We propose a framework to model on-line resource management problems based on an on-line version of positive linear programming. We consider both min cost problems and max benefit problems and propose logarithmic competitive algorithms that are optimal up to a constant factor. The proposed framework provides a general methodology that applies to a wide class of on-line problems: shop scheduling, packet routing, and in general a class of packing and assignment problems. Previously studied problems as on-line multiprocessor scheduling and on-line virtual circuit routing can also be modeled within this framework. Received December 18, 1996; revised March 2, 1997.     

CICS在银行系统中的应用

通过讲述中间件在联机事务处理中的应用来说明中间件在银行系统中的应用情况。交易中间件是专门应用于联机事务处理的一类中间件,而CICS正是一种交易中间件。文中对CICS交易中间件的基本组成和功能进行了说明,并分析了联机事务处理的基本特性及方式,主要选择了三种联机事务处理方式来说明,并分别分析了每一种联机交易处理方式的特点,最终选择了能更好保证事务完整性的交易中间件来实现联机交易的处理。     

CCITT X.500 Directories — principles and applications

Directories can be used as a service to provide human users or application processes with on-line access to what telecommunication services exist, where they reside, and how the correspondents might be accessed and addressed in a distributed environment. They will provide for the mapping of user-friendly recipient names to addresses in a consistent and standardized manner. In fact, any application which interacts with named objects in a distributed environment can benefit from the use of directory services.     

MSMiner—a developing platform for OLAP

Since the early 1970s, decision support systems (DSS) have evolved significantly. In this paper, the design and implementation of MSMiner, a developing platform for DSS, is introduced. The system is constructed on a data warehouse and integrated with a number of data mining algorithms. It is well suited for on-line analytical processing (OLAP). The characteristics of MSMiner include the ability to support multiple data sources and data mining strategies, additional organizational flexibility in regard to data and mining strategies, and the powerful expansibility of data mining tasks.     

Extrinsic versus intrinsic motivations for consumers to shop on-line

Previous research has usually assumed that shopping on-line is a goal-oriented activity and is motivated by extrinsic factors of the customers. On the other hand, intrinsic factors, such as entertainment, have been found to be a major reason for peoples to use the Internet. This study examined whether such intrinsic motivations can be used to explain consumers’ acceptance of on-line shopping. A theoretical model, based on the technology acceptance model, was proposed to describe the intrinsic and extrinsic motivations of consumers to shop on-line. Results of this empirical study showed that perceived usefulness is not an antecedent of on-line shopping, while fashion and a cognitive absorption experiences on the web were more important than their extrinsic factors in explaining on-line consuming behavior. Implications and limitations were discussed.     

基于Authorware的网络教学课件的设计与开发

采用Authorware多媒体制作工具和SQL编程技术,设计开发了多媒体技术基础及应用课程网络型多媒体教学课件。文章详细地阐述了课件总体结构的设计和子模块实现过程的几个关键技术。开发该系统的目的在于为学生提供一个网络学习环境,学生可以通过该环境进行课程的网上学习、网上答疑、网上提交作业、在线测试等,从而实现互动式的网上教学。     

On-line evolving image classifiers and their application to surface inspection

In this paper, we present image classifiers which are able to adapt and evolve themselves at an on-line machine vision system. These classifiers are initially trained on some pre-labelled training data and further updated based on newly recorded samples, for instance during a production process. The evolution and adaptation mechanism is necessary in order to guarantee a process-save on-line system as usually the pre-labelled data does not cover all possible operating conditions, system states or image classes. It is also recommended for a refinement of the classifiers during the on-line mode in order to boost predictive performance with more loaded samples. We will present two types of on-line evolving image classifiers: The first one is a clustering-based classification approach, which exploits conventional vector quantization, forming an incremental evolving variant around it and extending it to the supervised classification case. The second one is an evolving fuzzy classifier approach which comes with two model architectures, classical single model and a novel multi-model architecture, the later exploiting indicator matrices/vectors for training. The approaches are evaluated in three different on-line surface inspection systems dealing with CD imprint inspection, egg inspection and inspection of metal rotor parts. The evaluation will show the impact of on-line evolved versus ‘static’ classifiers kept fixed during the whole on-line process.     

在Internet上创建在线虚拟影院的研究

首先通过与传统在线影院在沉浸感、交互性、扩展性、商业性这四个方面的比较，概括了39在线虚拟影院的优点；然后分析了利用VRML语言在Internet上构建3D在线虚拟影院的可行性，并介绍了所要用到的关键技术；最后对虚拟现实技术在Internet上的发展做了一个概括性的小结。