Showing papers by "Nanyang Technological University published in 1995"

Markov Random Field Modeling in Computer Vision

Abstract: From the Publisher: Markov random field (MRF) theory provides a basis for modeling contextual constraints in visual processing and interpretation. It enables us to develop optimal vision algorithms systematically when used with optimization principles. This book presents a comprehensive study on the use of MRFs for solving computer vision problems. The book covers the following parts essential to the subject: introduction to fundamental theories, formulations of MRF vision models, MRF parameter estimation, and optimization algorithms. Various vision models are presented in a unified framework, including image restoration and reconstruction, edge and region segmentation, texture, stereo and motion, object matching and recognition, and pose estimation. This book is an excellent reference for researchers working in computer vision, image processing, statistical pattern recognition, and applications of MRFs. It is also suitable as a text for advanced courses in these areas.

Function representation in geometric modeling : concepts, implementation and applications

Abstract: Concepts of functionally based geometric modeling including sets of objects, operations, and relations are discussed. Transformations of a defining real function are described for set-theoretic operations, blending, offsetting, bijective mapping, projection, cartesian products, and metamorphosis. Inclusion, point membership, and intersection relations are also described. We use a high-level geometric language that can extend the interactive modeling system by input symbolic descriptions of primitives, operations, and predicates. This approach supports combinations of representational styles, including constructive geometry, sweeping, soft objects, voxel-based objects, deformable and other animated objects. Application examples of aesthetic design, collisions simulation, NC machining, range data processing, and 3D texture generation are given.

Role-Conflict, Ambiguity, and Overload - a 21-Nation Study

Abstract: The extent of role conflict, role ambiguity, and role overload reported by middle managers from 21 nations was related to national scores on power distance, individualism, uncertainty avoidance, an...

Automatic parsing of TV soccer programs

Abstract: While automatic parsing of general video images are difficult or nearly impossible, parsing a specific type of video image can be achieved if the video structure can be explicitly identified and its model can be constructed. The paper presents ongoing work on using domain knowledge to parse content of soccer video programs. The proposed system can classify a sequence of soccer frames into various play categories, such as shot at left goal, top left corner kick play in right penalty area, in midfield, etc, based on a priori model comprising four major components: a soccer court, a ball, the players and the motion vectors. Approaches in applying the model for parsing soccer programs are presented in detail. Experimental results are included to evaluate the performance of the system.

Why is There a Home Bias? An Analysis of Foreign Portfolio Equity Ownership in Japan

Abstract: This paper uses data on foreign stock ownership in Japan from 1975 to 1991 to examine the determinants of the home bias in portfolio holdings. Existing models of international portfolio choice predicting that foreign investors hold national market portfolios or portfolios tilted towards high expected return stocks are inconsistent with the evidence provided in this paper. We document that foreign investors overweight shares of firms in manufacturing industries, large firms, firms with good accounting performance, firms with low unsystematic risk, and firms with low leverage. Controlling for size, there is evidence that small firms that export more have greater foreign ownership. Foreign investors do not perform significantly worse than if they held the Japanese market portfolio, however. After controlling for firm size, there is no evidence that foreign ownership is related to expected returns of shares. We show that a model with size-based informational asymmetries and deadweight costs can yield asset allocations consistent with our evidence.

Performance and gain and phase margins of well-known PID tuning formulas

Abstract: The performance and robustness of well-known PID formulas for process with deadtime to time constant ratio between 0.1 and 1 are discussed in this paper. The Ziegler-Nichols, Cohen-Coon, and tuning formulas that optimize for load disturbance response (integral absolute error, integral squared error, and integral time-weighted absolute error) give gain margins of about 1.5. The phase margins increase from about 30 to 60/spl deg/ as the process deadtime to time constant ratio increases from 0.1 to 1. Tuning formulas that optimize setpoint response give gain margins of about two and phase margins of about 65/spl deg/. These formulas mostly make use of the proportional-integral derivative (PID) controller zeros to cancel the process poles. Approximate analytical formulas to compute gain and phase margins of PID control systems are also derived in this paper to facilitate online computation which would be particularly useful for implementing adaptive control.

Thermal and non-thermal interaction of microwave radiation with materials

Abstract: Industrial use of microwave radiation as an alternative to conventional thermal heating has generated interest recently mainly because of the drastic reduction in the processing time. In spite of its wide application, its chemical mechanism of interaction with materials has not been well understood. The current debate on the alternative use of microwave radiation to conventional thermal heating is on the involvement of a “microwave specific effect” other than the well accepted dielectric heating. There are reports of various reactions which show similar kinetics under both microwave and thermal methods at similar temperatures suggesting simple dielectric heating of materials by microwaves. There are also reports which show a clear reaction rate enhancement under microwave radiation compared to the thermal method under similar reaction conditions and temperatures indicating a “microwave specific effect” other than the simple dielectric heating of materials. This paper will discuss the above conflicting results reported in the literature.

Automatic parsing and indexing of news video

Abstract: Automatic construction of content-based indices for video source material requires general semantic interpretation of both images and their accompanying sounds; but such a broadly-based semantic analysis is beyond the capabilities of the current technologies of machine vision and audio signal analysis. However, if one can assume a limited and well-demarcated body of domain knowledge for describing the content of a body of video, then it becomes easier to interpret a video source in terms of that domain knowledge. This paper presents our work on using domain knowledge to parse news video programs and to index them on the basis of their visual content. Models based on both the spatial structure of image frames and the temporal structure of the entire program have been developed for news videos, along with algorithms that apply these models by locating and identifying instances of their elements. Experimental results are also discussed in detail to evaluate both the models and the algorithms that use them. Finally, proposals for future work are summarized.

First Sight: A human body outline labeling system

Abstract: First Sight, a vision system in labeling the outline of a moving human body, is proposed in this paper. The emphasis of First Sight is on the analysis of motion information gathered solely from the outline of a moving human object. Two main processes are implemented in First Sight. The first process uses a novel technique to extract the outline of a moving human body from an image sequence. The second process, which employs a new human body model, interprets the outline and produces a labeled two-dimensional human body stick figure for each frame of the image sequence. Extensive knowledge of the structure, shape, and posture of the human body is used in the model. The experimental results of applying the technique on unedited image sequences with self-occlusions and missing boundary lines are encouraging. >

Learning impedance control for robotic manipulators

Abstract: Most researches on learning control of constrained robots have been focused on the problem of hybrid position/force control where the learning controllers are designed to track the desired motion and force trajectories. The learning impedance control of robotic manipulators, however, has not been developed so far. In this paper, a learning impedance control problem for robotic manipulators is formulated and solved. A target impedance is specified and a learning controller is designed such that the system follows the desired response specified by the target model as the actions are repeated. Sufficient conditions for guaranteeing the convergence of the system are derived. Simulation results of a cylindrical robot are presented to illustrate the performances of the proposed learning impedance controller.

On discontinuity-adaptive smoothness priors in computer vision

Abstract: A variety of analytic and probabilistic models in connection with Markov random fields (MRFs) have been proposed in the last decade for solving low level vision problems involving discontinuities. This paper presents a systematic study of these models and defines a general discontinuity adaptive (DA) MRF model. By analyzing the Euler equation associated with the energy minimization, it shows that the fundamental difference between different models lies in the behavior of interaction between neighboring points, which is determined by the a priori smoothness constraint encoded into the energy function. An important necessary condition is derived for the interaction to be adaptive to discontinuities to avoid oversmoothing. This forms the basis on which a class of adaptive interaction functions (AIFs) is defined. The DA model is defined in terms of the Euler equation constrained by this class of AIFs. Its solution is C/sup 1/ continuous and allows arbitrarily large but bounded slopes in dealing with discontinuities. Because of the continuous nature, it is stable to changes in parameters and data, a good property for regularizing ill-posed problems. Experimental results are shown. >

Psychosocial Climate and Student Outcomes in Elementary Mathematics Classrooms: A Multilevel Analysis

Abstract: Associations between perceived psychosocial climate and student outcomes among a sample of 1,512 students in Grade 5 mathematics classes in Singapore were investigated. Two methods of analysis were used: multiple linear regression and hierarchical linear modeling. A comparison of findings from the two approaches suggests (a) the existence of associations between outcomes and environment and (b) the usefulness of incorporating both data analysis methods in learning-environment research.

The Muse Method for Usability Engineering

Abstract: MUSE is a method developed specifically to extend the scope of human factors contributions beyond late evaluation and thus increase their effectivness and uptake. This is accomplished by making inputs more explicit, early and continuous throughout the system development process. Since MUSE's scope spans user requirements to user interface design, it supports active human factors involvement in both design specification and evaluation. MUSE defines how, what and when particular human factor concerns should be addressed. It also specifies the procedures, notations, and documentation involved. This book will be essential reading for all involved with systems development, whether from the HCI or software engineering communities, and can be used as well for course accompaniment.

Who's got the power? Gender differences in partners' perceptions of influence during marital problem-solving discussions.

Abstract: Previous research on marital communication indicates that women have more influence in marital problem solving because they raise the issues and shape the discussion. Other studies suggest that men have the power in marital problem solving. This study re-examines power and influence from the partners' point of view. Twenty-seven couples-18 with a first child under 2, and 9 undecided about having children-were videotaped while working on a self-selected problem concerning their division of family labor. Data sources included: (a) transcribed audiotaped accounts given by each partner while viewing a videotape of their problem-solving discussion; (b) self-report questionnaires; and (c) ratings by a research team of the concordance between spouses' accounts. Husbands and wives were perceived as having a primary influence on different aspects of the discussion. Women tended to raise the issues and draw men out in the early phase of the discussion, while men controlled the content and emotional depth of the later discussion phases, and largely determined the outcome. The women's accounts emphasized that their influence in the early phase was often illusory: their behavior was shaped primarily by the effort to choose strategies that would avoid upsetting their husbands. In terms of overall satisfaction with marriage, wives had greater tolerance than their husbands for conflict in the area of division of domestic labor, but less tolerance for their husbands' domination of the discussion process. Women's marital satisfaction was higher when there was concordance between spouses in their accounts of their problem-solving discussion. This research highlights the importance of eliciting spouses' own perceptions and definitions in understanding the impact of gender-linked power differences in martial communication.

Use of ash derived from oil-palm waste incineration as a cement replacement material

Abstract: The production of palm oil creates large quantity of solid waste by-products. Empty oil-palm fruit bunches discharged from the mill are currently being disposed of by burning in an incinerator. After combustion, a substantial amount of highly caustic ash is produced which creates problems of disposal. This study examines the feasibility of using the ash as a cement replacement material. The experimental results indicate that blended cement containing ash derived from oil-palm waste shows satisfactory setting times and soundness test results. Workability of concrete incorporating the ash is categorized as good, and no segregation was observed. The effects of ash addition on concrete densities and water absorption are insignificant. Compressive strength of the concrete decreases with the ash content in the cement. Up to 10% by weight of ash addition, no adverse effect on the strength was observed for the cubes cured for 1 year. The results suggest that the ash could possibly be blended in small amounts with ordinary Portland cement for concrete making without detrimental effects on long-term strength property.