Versions Of Objects Research Articles

A classical approach for thinning of binary images using divergence of the potential field

In this paper, an algorithm for thinning of an object from its binary image is described. A generalized potential field is defined over the interior of the object and the divergence of the corresponding vector field is computed for each interior pixel. Then, those pixels of the object whose divergence values are above some specified threshold are selected, resulting in a thinned version of the original object. The density of the resulting skeletal structure can be controlled using different threshold values. The thinned version of the object obtained by this method can be used for image compression and shape matching.

Corner detection and curve segmentation by multiresolution chain-code linking

In this paper, we propose a new method to characterise a curve by means of the hierarchical computation of a multiresolution structure. This structure, consisting of successive lower resolution versions of the same object, is processed using the linked pyramid approach. We adapt the multiresolution pixel linking algorithm to the processing of curve contours which are described by their chain-code. We also introduce a selective class selection process which allows application of the algorithm to segmentation and detection of contour features. The resulting framework presents good performance for a wide range of object sizes without the need of any parameter tweaking, and allows detection of shape detail at different scales.

Applying multiple objective tabu search to continuous optimization problems with a simple neighbourhood strategy

One of the first multiple objective versions of the tabu search (TS) algorithm is proposed by the author. The idea of applying TS to multiple objective optimization is inspired from its solution structure. TS works with more than one solution (neighbourhood solutions) at a time and this situation gives the opportunity to evaluate multiple objectives simultaneously in one run. The selection and updating stages are modified to enable the original TS algorithm to work with more than one objective. In this paper, the multiple objective tabu search (MOTS) algorithm is applied to multiple objective non-linear optimization problems with continuous variables using a simple neighbourhood strategy. The algorithm is applied to four mechanical components design problems. The results are compared with several other solution techniques including multiple objective genetic algorithms. It is observed that MOTS is able to find better and much wider spread of solutions than the reported ones. Copyright © 2005 John Wiley & Sons, Ltd.

Inventorying Information Technology Systems: Supporting the "Paradigm of Change"

One of the most significant failures of the IT profession is the absence of systems to gather, support, and supply information for managing software items. Most IT professionals, if they consider software management, think in terms of version or configuration control license and patch management. Version control systems (VCSs) and software configuration management (SCM) systems aim to manage versions of individual software objects with support for linking into sets for release purposes. This has nothing to do with addressing the issues of controlling large amounts of geographically disbursed software, executing on different kinds of systems, maintained by hundreds to thousands of programmers. Software systems are the only major organizational asset with no real support for managing them based on information technology. An appropriate IT inventory management facility is the cornerstone of an integrated set of technologies, called the "paradigm of change" designed to address constantly changing technologies and business processes.

Temporal and versioning model for schema evolution in object-oriented databases

In this paper we define the Temporal and Versioning Model for Schema Evolution (TVSE), a model that uses time and version concepts to manage dynamic schema evolution in object-oriented databases. The proposed model is able to manage the schema evolution process considering: schema versioning, schema modification, change propagation and data manipulation. TVSE differs from other schema evolution models by enabling the homogeneous and simultaneous management of the evolution history concerning both intentional and extensional databases. Besides defining the model, we also propose a language to derive and modify schema versions, and also to update data associated with them, creating either new object versions or just keeping the history of these data modifications. We provide an operational semantics for this language which is an essential step towards for establishing the preservation of complex time integrity constraints.

Representational momentum in perception and grasping: translating versus transforming objects.

Representational momentum is the tendency to misremember the stopping point of a moving object as further forward in the direction of movement. Results of several studies suggest that this effect is typical for changes in position (e.g., translation) and not for changes in object shape (transformation). Additionally, the effect seems to be stronger in motor tasks than in perceptual tasks. Here, participants judged the final distance between two spheres after this distance had been increasing or decreasing. The spheres were two separately translating objects or were connected to form a single transforming object (a dumbbell). Participants also performed a motor task in which they grasped virtual versions of the final objects. We found representational momentum for the visual judgment task for both stimulus types. As predicted, it was stronger for the spheres than for the dumbbells. In contrast, for grasping, only the dumbbells produced representational momentum (larger maximum grip aperture when the dumbbells had been growing compared to when they had been shrinking). Because type of stimulus change had these different effects on representational momentum for perception and action, we conclude that different sources of information are used in the two tasks or that they are governed by different mechanisms.

Configuration management in evolutionary engineering design using versioning and integrity constraints

Artifacts in engineering design are structurally complex and may be represented in software as recursively composite objects. Due to the evolutionary nature of the design process each artifact and its components may evolve through several versions. The paper describes enhanced database system facilities that are used to group mutually consistent component versions together into useful configurations. The versioning system includes integrity management facilities that allow evolving design constraints to be captured flexibly at individual component/object level. In order to permit evolution, integrity constraints are represented within versionable objects, so-called constraint version objects (CVOs). Inter-dependency constraints can be modelled to express the consistency semantics necessary to combine component object versions into useful configurations. The evolution of these configurations can be captured in the database, as configurations are also represented as versioned objects. As a result of the hierarchical structure of composite artifact objects, subconfigurations may be combined to form higher-level configurations. To overcome the difficulties associated with combining object versions and subconfigurations into meaningful configurations, the computer system provides a graphical user interface which greatly eases the task of the designer. Selection of the mutually consistent object versions making up a configuration and the associated integrity validation is facilitated by the system, thus removing the need for the designer to become involved in any form of computer programming.

Configuration management in evolutionary engineering design using versioning and integrity constraints

Artifacts in engineering design are structurally complex and may be represented in software as recursively composite objects. Due to the evolutionary nature of the design process each artifact and its components may evolve through several versions. The paper describes enhanced database system facilities that are used to group mutually consistent component versions together into useful configurations. The versioning system includes integrity management facilities that allow evolving design constraints to be captured flexibly at individual component/object level. In order to permit evolution, integrity constraints are represented within versionable objects, so-called constraint version objects (CVOs). Inter-dependency constraints can be modelled to express the consistency semantics necessary to combine component object versions into useful configurations. The evolution of these configurations can be captured in the database, as configurations are also represented as versioned objects. As a result of the hierarchical structure of composite artifact objects, subconfigurations may be combined to form higher-level configurations. To overcome the difficulties associated with combining object versions and subconfigurations into meaningful configurations, the computer system provides a graphical user interface which greatly eases the task of the designer. Selection of the mutually consistent object versions making up a configuration and the associated integrity validation is facilitated by the system, thus removing the need for the designer to become involved in any form of computer programming.

WALRUS: a similarity retrieval algorithm for image databases

Approaches for content-based image querying typically extract a single signature from each image based on color, texture, or shape features. The images returned as the query result are then the ones whose signatures are closest to the signature of the query image. While efficient for simple images, such methods do not work well for complex scenes since they fail to retrieve images that match the query only partially, that is, only certain regions of the image match. This inefficiency leads to the discarding of images that may be semantically very similar to the query image since they may contain the same objects. The problem becomes even more apparent when we consider scaled or translated versions of the similar objects. We propose WALRUS (wavelet-based retrieval of user-specified scenes), a novel similarity retrieval algorithm that is robust to scaling and translation of objects within an image. WALRUS employs a novel similarity model in which each image is first decomposed into its regions and the similarity measure between a pair of images is then defined to be the fraction of the area of the two images covered by matching regions from the images. In order to extract regions for an image, WALRUS considers sliding windows of varying sizes and then clusters them based on the proximity of their signatures. An efficient dynamic programming algorithm is used to compute wavelet-based signatures for the sliding windows. Experimental results on real-life data sets corroborate the effectiveness of WALRUS'S similarity model.

Optical processing with vortex-producing lenses.

We discuss two types of optical processing using vortex-producing angular phase plates. In the most common spatial-filtering operation, an input object is Fourier transformed (either by Fraunhofer diffraction or with a lens system). The Fourier transform is then multiplied by an angular phase pattern, and the product is again Fourier transformed. The output is a space-invariant, edge-enhanced version of the input object. Alternatively we can directly image the object using a lens multiplied by the angular phase. The space-variant image is severely distorted along the optical axis of the system. We encode the phase plates onto a liquid-crystal display and present experimental results on both systems.

On exploring aggregate effect for efficient cache replacement in transcoding proxies

Recent technology advances in mobile networking have ushered in a new era of personal communication. Users can ubiquitously access the Internet via many emerging mobile appliances, such as portable notebooks, personal digital assistants (PDAs), and WAP-enabled cellular phones. While the transcoding proxy is attracting an increasing amount of attention in this environment, it is noted that new caching strategies are required for these transcoding proxies. We propose an efficient cache replacement algorithm for transcoding proxies. Specifically, we formulate a generalized profit function to evaluate the profit from caching each version of an object. This generalized profit function explicitly considers several new emerging factors in the transcoding proxy and the aggregate effect of caching multiple versions of the same object. It is noted that the aggregate effect is not simply the sum of the costs of caching individual versions of an object, but rather, depends on the transcoding relationship among these versions. The notion of a weighted transcoding graph is devised to evaluate the corresponding aggregate effect efficiently. Utilizing the generalized profit function and the weighted transcoding graph, we propose, in this paper, an innovative cache replacement algorithm for transcoding proxies. In addition, an effective data structure is designed to facilitate the management of the multiple versions of different objects cached in the transcoding proxy. Using an event-driven simulation, it is shown that the algorithm proposed consistently outperforms companion schemes in terms of the delay saving ratios and cache hit ratios.

Design-Optimization of Mechanical Components Using the “Multiple Objective Tabu Search” Method

The multiple objective version of the tabu search (TS algorithm was initially developed by Baykasoglu et al [1-3]. The idea of applying tabu search to multiple objective optimization, inspired from its solution structure, in which tabu search works with more than one solution (neighborhood solutions) at a time. This situation creates the opportunity to evaluate multiple objectives simultaneously in one run. To enable the original tabu search algorithm to work with more than one objective the selection and updating stages were redefined. Other stages are identical to the original tabu search algorithm. In this paper, mutiple objective tabu search algorithm is used to solve mechanical component design problems) with multiple objectives. Although there exists a number of classical techniques, meta-heuristic algorithms including TS have an edge over the classical methods in that they can find multiple Pareto-optimal solutions in one single run. In the paper four mechanical component design problems borrowed from the literature are solved. The results are compared with several other solution techniques including multiple objective genetic algorithms. It is observed that in many of the cases the multiple objective tabu search algorithm can find better and much wider spread of solutions than the compared algorithms.

A study of object declustering strategies in parallel temporal object database systems

In a transaction-time temporal object database management system (TODBMS), updating an object creates a new version of the object, but the old version is still accessible. A TODBMS will store large amounts of data, and in order to provide the necessary computing power and data bandwidth, a parallel system based on a shared-nothing architecture is necessary. In order to benefit from a parallel architecture, a suitable declustering of the objects over the nodes in the system is important. In this paper, we study three low-cost declustering algorithms: (1) declustering based on the hash value of the OID of the objects, (2) range partitioning based on the timestamp of the objects, and (3) a new hybrid algorithm, where current object versions are declustered according to the hash value of the OID, and the historical versions are range partitioned based on timestamp. In contrast to many similar studies, we study the performance with a workload including both read and update operations. We show that strategies 1 and 3 are the most scalable strategies, and that the new hybrid declustering strategy is especially suitable for low update rates, for example in geographical information systems and decision support systems with support for temporal data. However, in general declustering based on the hash value of the OID of the objects has the most stable and predictable performance.

An integrity constraint management framework in engineering design

Due to the evolutionary nature of the engineering design process it is necessary to provide support for version management. The version model should be provided with an integrity checking mechanism to assure the consistency of object versions with the design constraints. Managing integrity constraints is complex due to their evolving nature and raises number of issues that need to be dealt with. In this paper we present a conceptual framework for providing an integrity mechanism for object versions and show how it operates in a co-operative and distributed design environment. The framework is based on the concept of the constraint version object (CVO).

Consistency maintenance in real-time collaborative graphics editing systems

Real-time collaborative graphics editing systems allow a group of users to view and edit the same graphics document at the same time from geographically dispersed sites connected by communication networks. Consistency maintenance in the face of concurrent accesses to shared objects is one of the core issues in the design of these types of systems. In this article, we propose an object-level multiversioning approach to consistency maintenance in real-time collaborative graphic editors. This approach is novel in achieving intention preservation and convergence, in preserving the work concurrently produced by multiple users in the face of conflict, and in minimizing the number of object versions for conflict resolution. Major technical contributions of this work include a formal specification of a unique combined effect for an arbitrary group of conflict and compatible operations, a distributed algorithm for incremental creation of multiple object versions, a consistent object identification scheme for multiple object versions, and a convergent layering scheme for overlapping objects. All algorithms and schemes presented in this article have been implemented in an Internet-based GRACE (graphics collaborative editing) system.

2차원 지리 객체를 위한 시공간 객체 모델 설계

지금까지 시공간 객체를 다양한 관점에서 접근하여 표현하려는 많은 연구가 이루어졌다. 이 대부분의 연구는 GIS적 관점과 시간 데이터베이스 관점, 그리고 객체 지향적 관점 및 데이터타입 접근 방법으로 시공간 객체를 표현하고 있다. 시공간 객체는 공간 속성이 불연속적으로 변하는 객체, 위치 정보가 연속적으로 변하는 객체, 그리고 면적과 위치가 연속적으로 변하는 객체로 분류된다. 그러나 기존의 시공간 모델들은 한 종류의 객체에만 초점을 맞추고 있다. 따라서 이 논문에서는 유클리드 평면상에서 세가지 형태의 객체를 모두 표현할 수 있는 시공간 객체 모델을 제안한다. 이를 위해 유효시간 개념을 확장한 시간 모델과 함께 객체의 연속된 두 버전간의 관계성을 정의하여 이동 객체와 이력 객체 모두를 표현하는 방식을 사용한다. 여기서 제안하는 2차원 시공간 객체 모델은 개방형 GIS 명세서에서 제시하고 있는 2차원 공간 객체 모델을 따름으로써 표준 공간 모델과의 호환성을 보장한다. Most of works have been performed on representation of spatiotemporal objects from various points of view. Most of them represent spatiotemporal objects using approaches from GIS, temporal databases, object-oriented databases or data type. Spatiotemporal objects can be classified as objects whose position and shape changes discretely over time, objects whose position changes continuously and objects whose shape changes continuously as well as position. Previous works on spatiotemporal model have focused on only one of them. In this paper, we propose a spatiotemporal model that can represent three types of objects in Euclidean plan. For this purpose, we represent both discrete and continuous moving objects by defining temporal model extended from valid time and by defining relationship between two consecutive versions of objects. The proposed spatiotemporal object model is based on open GIS specification so that it has compatibility with existing spatial data model.

User-friendly visualization of object versions and archives in collaborative computer work

Data, states, events, information, experience and knowledge are present in all production enterprises in a vast array of forms. There is a common trend for storage, administration and processing of these in a distributed and connected information system for collaborative computer work. Work objects and data in a shared computer application can be continually changed and modified by different users working simultaneously with this application. Due to the different versions and the history of a common working object it becomes more and more important to be aware of the various states of the object. Within a recently completed comparative investigation study at the 'Laboratory for Human-Machine-Interaction' of the ifab-Institute, different ways of visualizing object versions and archives were evaluated. The investigation was based on different structured visualization forms.

FIXED-ORDER DISSIPATIVE ESTIMATOR DESIGN FOR UNCERTAIN STOCHASTIC SYSTEMS

A general class of discrete-time uncertain nonlinear stochastic systems with quadratic sum constraints is considered. A linear fixed order state estimator for state estimation is presented for various estimation error performance criteria in a unified framework. The observer is of order equal to the difference between the state and output vector dimensions. The performance criteria considered in this paper include guaranteed-cost suboptimal versions of estimation objectives like H2, H∞, stochastic passivity, etc. The design of fixed-order linear state estimators that satisfy these criteria are given using a common matrix inequality formulation.

A Non-authoritative Educational Metadata Ontology for Filtering and Recommending Learning Objects

Digital libraries populated with learning objects are becoming popular tools in the creation of instructional technologies. Many current efforts to create standard metadata structures that facilitate the discovery and instructional use of learning objects recommend a single, authoritative metadata record per version of the learning object. However, as we argue in this paper, a single metadata record — particularly one with fields that emphasize knowledge management and technology, while evading instructional issues — provides information insufficient to support instructional utilization decisions. To put learning objects to instructional use, users must examine the individual objects, forfeiting the supposed benefits of the metadata system. As a solution, we propose a system that includes multi-record, non-authoritative metadata focussed on the surrounding instructional context of learning objects.

Psychometric Properties of a Spanish Version of the McGill Pain Questionnaire in Several Spanish-Speaking Countries

Versions of the McGill Pain Questionnaire are available in a several languages and are used in clinical studies and sociocultural or ethnic comparisons of pain issues. However, there is a lack of studies that compare the validity and reliability of the instrument in the countries where it is used. The current study investigates the psychometric properties of a Spanish version of the McGill Pain Questionnaire in five Spanish-speaking countries. The authors conducted a multicenter and transnational study with one investigator in each center. Patients were evaluated once with a Spanish version of the McGill Pain Questionnaire, a visual analog scale, and a verbal rating scale. The study was performed in pain clinics and acute pain units of four Latin American countries (Argentina, Costa Rica, Mexico, and Panama) and Spain. The study included 205 patients (84 with acute pain, 121 with chronic pain) from Latin America. Their data were compared with those of 282 Spanish patients. The McGill Pain Questionnaire, visual analog scale, and verbal rating scale were administered once to all patients. The McGill Pain Questionnaire was administered again to patients from Latin America countries to ascertain descriptor comprehension. Demographic data, McGill Pain Questionnaire parameters, and visual analog scale and a verbal rating scale scores were obtained from patients with chronic and acute pain. Psychometric properties of the Spanish version of the McGill Pain Questionnaire were established for each country by calculating the ordinal consistency by means of rank-scale correlation (Spearman test), intercategory correlation, and interparameter correlation (Pearson test). Concurrent validity was also calculated by comparing scores from the visual analog scale (Pearson test) and verbal rating scale (Spearman test) with questionnaire parameters (qualitative-to-quantitative comparisons). The Spanish version of the McGill Pain Questionnaire maintained a high internal validity when tested in different countries. Ordinal consistency, intercategory, interparameter, and qualitative-to-quantitative parameter correlations were similar in all countries. Few descriptors were considered to be inappropriate or difficult to understand. The psychometric properties of the Spanish version of the McGill Pain Questionnaire assessed in different Latin-American countries suggest that the questionnaire may be used to evaluate Spanish-speaking patients. The validity of this test should be extended with reliability studies to further establish its usefulness in the evaluation of pain.