bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of amino acids as formamidene butyl esters by electrospray ionization tandem mass spectrometry
Authors: Johnson David W.
Published: August 2002

Amino acid formamidene butyl esters are optimally prepared by heating amino acids with dimethylformamide dimethylacetal (DMF‐DMA) for 2 minutes at 65 °C and then with n‐butanol/hydrogen chloride for 15 minutes at 65 °C. The formamidene butyl esters of simple α‐amino acids and β‐amino acids afford between 1.1 and 20 times the signal intensity of the corresponding butyl esters during electrospray ionization tandem mass spectral analysis. Complex α‐amino acids, such as ornithine, arginine and citrulline, and γ‐amino acids are better analyzed as butyl esters. Secondary α‐amino acids, such as proline and sarcosine, give a mixture of two iminium salts with the DMF‐DMA derivatization method. A derivative incorporating two molecules of the amino acid predominates at higher derivatization temperatures. Contrary to a previous report, N‐formylamino acids were not detected. The presence of secondary amino acids in amino acid mixtures, derivatized as formamidene butyl esters, affords derivatives that incorporate two different amino acids. The new formamidene butylation method is unlikely to replace the butylation procedure used by neonatal blood spot screening programs for amino acid disorders, since a much poorer response was obtained with formamidene butyl esters of arginine and citrulline, important in the diagnosis of arginase deficiency and citrullinaemia. Copyright © 2001 John Wiley & Sons, Ltd.
India Ink staining after sodium dodecyl sulfate polyacrylamide gel electrophoresis and in conjunction with Western blots for peptide mapping by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Klarskov Klaus , Naylor Stephen
Published: August 2002

We present an approach that allows matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometric (MALDI‐TOFMS) peptide mapping of proteins separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) and electroblotted onto nitrocellulose (NC). After blocking the nitrocellulose membrane with polyvinylpyrrolidone‐40 the immobilized proteins are visualized using India Ink staining which allows the detection of low nanogram amounts of protein. The utilization of a low concentration of Tween 20 (0.05%) in the India Ink staining solution does not negatively impair the quality of the mass spectra. Due to the virtual nondestructive nature of the stain proteolytic peptides could be recovered from the NC membrane. Taking into account minor precautions during the sample manipulation and concentration and by loading the sample onto a pre‐crystallized matrix layer, high quality mass spectral data were obtained on <100 femtomoles of protein loaded onto the gel. Finally, the use of India Ink in conjunction with Western blot analysis is also demonstrated. A rat plasma protein, characterized by Western blot as a covalently modified protein‐drug compound, was subjected to peptide mapping and post source decay (PSD) sequencing of peptides. The zomepirac‐modified protein was identified as the alpha‐subunit of fibrinogen. Copyright © 2001 John Wiley & Sons, Ltd.
Linear QFT control of a highly nonlinear multi‐machine power system
Authors: Kelemen Matei , Akhrif Ouassima
Published: August 2002

A quantitative feedback theory (QFT) method of Horowitz, treating nonlinearities as equivalent disturbances, is applied to the linear control of a multi‐machine power system. This system has a smooth nonlinear dynamics so the original approach was simplified. From the design point of view good results were obtained with simple controllers (automatic voltage regulator, speed governor, power system stabilizer) when the power system was affected by large load variations and short circuits. To reduce significantly the steady state errors which appeared, a novel rotor speed error amplification scheme was employed. This increased the autonomy of the controlled power system to combat big distortions from normal operating conditions. Copyright © 2001 John Wiley & Sons, Ltd.
Survey of quantitative feedback theory (QFT)
Authors: Horowitz Isaac
Published: August 2002

QFT is an engineering design theory devoted to the practical design of feedback control systems. The foundation of QFT is that feedback is needed in control only when plant (P), parameter and/or disturbance (D) uncertainties (sets 𝒫={P}, 𝒟={D}) exceed the acceptable (A) system performance uncertainty (set 𝒜={A}). The principal properties of QFT are as follows. (1) The amount of feedback needed is tuned to the (𝒫, 𝒟, 𝒜) sets. If 𝒜 ‘exceeds’ (𝒫, 𝒟), feedback is not needed at all. (2) The simplest modelling is used: (a) command, disturbance and sensor noise inputs, and (b) the available sensing points and the defined outputs. No special controllability test is needed in either linear or non‐linear plants. It is inherent in the design procedure. There is no observability problem because uncertainty is included. The number of independent sensors determines the number of independent loop transmissions (Li), the functions which provide the benefits of feedback. (3) The simplest mathematical tools have been found most use ful—primarily frequency response. The uncertainties are expressed as sets in the complex plane. The need for the larger 𝒫, 𝒟 sets to be squeezed into the smaller 𝒜 set results in bounds on theLi(jω) in the complex plane. In the more complex systems a key problem is the division of the ‘feedback burden’ among the availableLi(jω). Point‐by‐point frequency synthesis tremendously simplifies this problem. This is also true for highly uncertain non‐linear and time‐varying plants which are converted into rigorously equivalent linear time invariant plant sets and/or disturbance sets with respect to the acceptable output set 𝒜. Fixed point theory justifies the equivalence. (4) Design trade‐offs are highly transparent in the frequency domain: between design complexity and cost of feedback (primarily bandwidth), sensor noise levels, plant saturation levels, number of sensors needed, relative sizes of 𝒫, 𝒜 and cost of feedback. The designer sees the trade‐offs between these factors as he proceeds and can decide according to their relative importance in his particular situation.

QFT design techniques with these properties have been developed step by step for: (i) highly uncertain linear time invariant (LTI) SISO single‐ and multiple‐loop systems, MIMO single‐loop matrix and multiple‐loop matrix systems; and (ii) non‐linear and time‐varying SISO and MIMO plants, and to a more limited extent for plants with distributed control inputs and sensors. QFT has also been developed for single‐ and multiple‐loop dithered non‐linear (adaptive) systems with LTI plants, and for a special class (FORE) of non‐linear compensation. New techniques have been found for handling non‐minimum‐phase (NMP) MIMO plants, plants with both zeros and poles in the right half‐plane and LTI plants with incidental hard non‐linearities such as saturation.
Developing a fault tolerant power‐train control system by integrating design of control and diagnostics
Authors: Kim Yong‐Wha , Rizzoni Giorgio , Utkin Vadim I.
Published: August 2002

Fault detection, isolation and fault tolerant control are investigated for an spark ignition engine. Fault tolerant control refers to a strategy in which the desired stability and robustness of the control system are guaranteed in the presence of faults. In an attempt to realize fault tolerant control, a methodology for integrated design of control and fault diagnostics is proposed. Specifically, the integrated design of control and diagnostics is achieved by combining the integral sliding mode control methodology and observers with hypothesis testing. Information obtained from integral sliding mode control and from observers with hypothesis testing is utilized so that a fault can be detected, isolated and compensated. As an application example, the air and fuel dynamics of an IC engine are considered. A mean value engine model is developed and implemented in Simulink®. The air and fuel dynamics of the engine are identified using experimental data. The proposed algorithm for integration of control and diagnostics is then validated using the identified engine model. Copyright © 2001 John Wiley & Sons, Ltd.
Feasibility in predictive control of constrained linear systems: the output feedback case
Authors: Chisci Luigi , Zappa Giovanni
Published: August 2002

This paper addresses model‐based predictive regulation for a linear discrete‐time system in the presence of unknown but bounded disturbances, partial state information and state/control constraints. The proposed nonlinear dynamic compensator uses a set‐valued estimator, which recursively updates the membership set of the plant state, along with a receding‐horizon regulator which selects on‐line the control variable depending upon the current state membership set. It is shown that the overall scheme preserves feasibility if this is assumed from the outset, and hence guarantees closed‐loop stability and constraint fulfilment. These properties rely on exact set‐membership estimation. A simple approximation scheme which avoids set‐membership estimation but preserves stability is also proposed and the relative performance/complexity tradeoffs are discussed. Simulation results demonstrate the effectiveness of the proposed method. Copyright © 2002 John Wiley & Sons, Ltd.
IQC robustness analysis for time‐delay systems
Authors: Jun Myungsoo , Safonov Michael G.
Published: August 2002

Stability robustness of systems with uncertain time delays is considered. A new delay‐dependent state‐space stability criterion is formulated in the form of an easily checked LMI condition. Two applications of the main result are presented, one with only time‐delay uncertainty and one with both delay and parametric uncertainty. Copyright © 2001 John Wiley & Sons, Ltd.
Active force closure for multiple objects
Authors: Harada Kensuke , Kaneko Makoto , Tsuji Toshio
Published: August 2002

This article discusses active force closure (AFC) for the manipulation of multiple objects. AFC for multiple objects is defined in such a way that the finger can generate an arbitrary acceleration onto a certain point of multiple objects. We define two kinds of AFC: in the first, an arbitrary acceleration can be generated onto each of the objects; in the second, an arbitrary acceleration can be generated onto the center of mass of multiple objects without changing the relative position of the objects. We show that the grasped object cannot always be manipulated arbitrarily even if the first kind of AFC is satisfied. We also show that the grasped objects are manipulated like a single rigid body if the second kind of AFC is satisfied. To explain these features of AFCs, numerical examples for the grasp of three objects are shown. © 2002 Wiley Periodicals, Inc.
Realization of those elastic behaviors that have compliant axes in compact elastic mechanisms
Authors: Huang Shuguang , Schimmels Joseph M.
Published: August 2002

In this article, we address the synthesis and realization of a subset of spatial elastic behaviors, those with compliant axes, in compact parallel mechanisms. Using the procedures developed, a geometric description of the layout of a compact mechanism of springs connected in parallel is obtained. In each of these mechanisms, each spring axis is restricted to intersect a single point in space. The variation in the orientation of the intersecting spring axes is also restricted. The degree of restriction in axis orientation is determined by the number of “compliant axes” associated with the specified elastic behavior. Also, as part of this work, a physical appreciation of the different classes of stiffnesses that have compliant axes is identified and interpreted in different types of concurrent parallel mechanisms. © 2002 Wiley Periodicals, Inc.
Stiffness characteristics and kinematics analysis of two‐link elastic underactuated manipulators
Authors: Dai Jian S. , Zhao Tie Shi
Published: August 2002

This article investigates the stiffness characteristics of two‐link underactuated manipulators, examines the effect on the torque resulting in the passive joint, and develops a stiffness model in analysing the behaviors of the manipulators. The kinematic analysis leads to the trajectory of the end‐effector, which is associated with the stiffness coupled between the active and passive joints and with the constraint forces, and the kinematic coupling is shown in the angular displacement and in the resulting torque. The stiffness characteristics are illustrated in the directional stiffness mapping, which gives a quantitative measure of stiffness with respect to displacement direction. © 2002 Wiley Periodicals, Inc.
Locomotion characteristics of an SMA‐actuated micro robot simulating a medicinal leech in a pipeline
Authors: Liu Fang‐Hu , Ma Pei‐Sun , Chen Jian‐Ping , Zhu Jie , Yao Qin
Published: August 2002

Research into the locomotion principle of a new micro peristaltic robot simulating a medicinal leech in a pipeline, and a subsequent kinematic model, inform this article. The effects of structure on robot performance are analyzed; also presented is the basis for the robot's redesign, parameterized design, and optimal design. © 2002 Wiley Periodicals, Inc.
A tetrahedron approach for a unique closed‐form solution of the forward kinematics of six‐dof parallel mechanisms with multiconnected joints
Authors: Song Se‐Kyong , Kwon Dong‐Soo
Published: August 2002

This article presents a new formulation approach that uses tetrahedral geometry to determine a unique closed‐form solution of the forward kinematics of six‐dof parallel mechanisms with multiconnected joints. For six‐dof parallel mechanisms that have been known to have eight solutions, the proposed formulation, called theTetrahedron Approach, can find a unique closed‐form solution of the forward kinematics using the three proposed Tetrahedron properties. While previous methods to solve the forward kinematics involve complicated algebraic manipulation of the matrix elements of the orientation of the moving platform, or closed‐loop constraint equations between the moving and the base platforms, the Tetrahedron Approach piles up tetrahedrons sequentially to directly solve the forward kinematics. Hence, it allows significant abbreviation in the formulation and provides an easier systematic way of obtaining a unique closed‐form solution. © 2002 Wiley Periodicals, Inc.
Planning and controlling cooperating robots through distributed impedance
Authors: Szewczyk Jérôme , Plumet Frédéric , Bidaud Philippe
Published: August 2002

This article presents distributed impedance as a new approach for multiple robot system control. In this approach, each cooperating manipulator is controlled by an independent impedance controller. In addition, along selected degrees of freedom, force control is achieved through an external loop, to improve control of the object's internal loading. Extensive stability analysis is performed, based on a realistic model that includes robot impedance and object dynamics. Experiments are performed using two cooperating industrial robots holding an object through point contacts. Force and position control actions are suitably dispatched to achieve both internal loading control and object position control. Individual impedance parameters are specified according to the theoritical stability criterion. The performance of the system is demonstrated for transportation and contact tasks. © 2002 Wiley Periodicals, Inc.
Fusing force and vision feedback for manipulating deformable objects
Authors: Luo Yanhong , Nelson Bradley J.
Published: August 2002

This article describes a framework that fuses vision and force feedback for the control of highly deformable objects. Deformable active contours, or snakes, are used to visually observe changes in object shape over time. Finite‐element models of object deformations are used with force feedback to predict expected visually observed deformations. Our approach improves the performance of large, complex deformable contour tracking over traditional computer vision tracking techniques. This same approach of combining deformable active contours with finite‐element material models is modified so that a vision sensor, i.e., a charge‐coupled device (CCD) camera, can be used as a force sensor. By visually tracking changes in contours on the object, material deflections can be transformed into applied stress estimates through finite element modeling. Therefore, internal object stresses due to object manipulation can be visually observed and controlled, thus creating a framework for deformable object manipulation. A pinhole camera model is used to accomplish vision and force sensor feedback assimilation from these two sensing modalities during manipulation. © 2001 John Wiley & Sons, Inc.
Point‐to‐point and multi‐goal path planning for industrial robots
Authors: Wurll Christian , Henrich Dominik
Published: August 2002

This article presents contributions in the field of path planning for industrial robots with 6 degrees of freedom. This work presents the results of our research in the last 4 years at the Institute for Process Control and Robotics at the University of Karlsruhe. The path planning approach we present works in an implicit and discretized C‐space. Collisions are detected in the Cartesian workspace by a hierarchical distance computation. The method is based on the A* search algorithm and needs no essential off‐line computation. A new optimal discretization method leads to smaller search spaces, thus speeding up the planning. For a further acceleration, the search was parallelized. With a static load distribution good speedups can be achieved. By extending the algorithm to a bidirectional search, the planner is able to automatically select the easier search direction. The new dynamic switching of start and goal leads finally to the multi‐goal path planning, which is able to compute a collision‐free path between a set of goal poses (e.g., spot welding points) while minimizing the total path length. © 2001 John Wiley & Sons, Inc.
Humanoids and personal robots: Design and experiments
Authors: Dario Paolo , Guglielmelli Eugenio , Laschi Cecilia
Published: August 2002

This paper addresses the field of humanoid and personal robotics—its objectives, motivations, and technical problems. The approach described in the paper is based on the analysis of humanoid and personal robots as an evolution from industrial to advanced and service robotics driven by the need for helpful machines, as well as a synthesis of the dream of replicating humans.

The first part of the paper describes the development of anthropomorphic components for humanoid robots, with particular regard to anthropomorphic sensors for vision and touch, an eight‐d.o.f. arm, a three‐fingered hand with sensorized fingertips, and control schemes for grasping. Then, the authors propose a user‐oriented design methodology for personal robots, and describe their experience in the design, development, and validation of a real personal robot composed of a mobile unit integrating some of the anthropomorphic components introduced previously and aimed at operating in a distributed working environment.

Based on the analysis of experimental results, the authors conclude that humanoid robotics is a tremendous and attractive technical and scientific challenge for robotics research. The real utility of humanoids has still to be demonstrated, but personal assistance can be envisaged as a promising application domain. Personal robotics also poses difficult technical problems, especially related to the need for achieving adequate safety, proper human–robot interaction, useful performance, and affordable cost. When these problems are solved, personal robots will have an excellent chance for significant application opportunities, especially if integrated into future home automation systems, and if supported by the availability of humanoid robots. © 2001 John Wiley & Sons, Inc.
A unified framework for obtaining improved approximation algorithms for maximum graph bisection problems
Authors: Halperin Eran , Zwick Uri
Published: August 2002

We obtain improved semidefinite programming based approximation algorithms forallthe natural maximum bisection problems of graphs. Among the problems considered are: MAX$n\over 2$‐BISECTION—partition the vertices of the graph into two sets of equal size such that the total weight of edges connecting vertices from different sides is maximized; MAX$n\over 2$‐VERTEX‐COVER—find a set containing half of the vertices such that the total weight of edges touching this set is maximized; MAX$n\over 2$‐DENSE‐SUBGRAPH—find a set containing half of the vertices such that the total weight of edges connecting two vertices from this set is maximized; and MAX$n\over 2$UNCUT—partition the vertices into two sets of equal size such that the total weight of edges that donotcross the cut is maximized. We also consider the directed versions of these problems, such as MAX$n\over 2$‐DIRECTED‐BISECTION and MAX$n\over 2$‐DIRECTED‐UNCUT. These results can be used to obtain improved approximation algorithms for the unbalanced versions of the partition problems mentioned above, where we want to partition the graph into two sets of size$k$and$n - k$, where$k$is not necessarily$n\over 2$. Our results improve, extend and unify results of Frieze and Jerrum, Feige and Langberg, Ye, and others. All these results may be viewed as extensions of the MAX CUT algorithm of Goemans and Williamson, and the MAX 2‐SAT and MAX DI‐CUT algorithms of Feige and Goemans. © 2002 Wiley Periodicals, Inc. Random Struct. Alg., 20:382–402, 2002
Providing multimedia communications services from high altitude platforms
Authors: Grace D. , Daly N. E. , Tozer T. C. , Burr A. G. , Pearce D. A. J.
Published: August 2002

System level design considerations for high altitude platforms operating in the mm‐wave bands are examined. Propagation effects in these bands are outlined, followed by a brief introduction to different platform scenarios. Ground‐based and platform‐based fixed wireless access scenarios are considered, and it is shown that using a platform, a single base station can supply a much larger coverage area than a terrestrial base station. The effects on performance of platform displacement from its desired location with both fixed and steerable antennas are also examined. It is shown that steerable antennas are of most use when fixed stations are immediately below the platform, with no benefit for fixed stations on the edge of coverage. The bandwidths required to serve several traffic distributions (suburbs and city centre based) are evaluated using the Shannon equation. It is shown that capacity can be constrained when users are located in the city centres, despite longer line of sight paths to users out in the suburbs. The effects of temporal changes in the spatial traffic distribution are investigated. It is shown that bandwith requirements can be reduced if the platform moves to track these changes. Copyright © 2001 John Wiley & Sons, Ltd.
The case of Carla: Dilemmas of helpingallstudents to understand science
Authors: Kurth Lori A. , Anderson Charles W. , Palincsar Annemarie S.
Published: August 2002

This paper tells the story of four sixth‐grade students, of mixed race and social class, who worked together in a small group. All four students were intrigued as they experimented with colored solutions of different densities. They all wanted to share ideas about the techniques they had used, the observations they had made, and the patterns they had seen. They all wanted to understand why the colored solutions acted as they did. In spite of these common interests, they often failed to achieve intersubjective communication about the colored solutions or about the process of planning and making a poster to report their findings. We explain these failures using the sociolinguistic concepts of polysemy, privileging, and holding the floor. In particular, Carla (an African American girl) was unable to hold the floor within the group, so her opportunities for science learning were diminished. The four students were not overtly prejudiced in their speech or actions. Yet the expectations they brought with them about how and when people should talk, how work should be done, and what standards of quality they should aspire to led them to reconstruct among themselves some of the most troubling inequities of our society as a whole. This story is about important connections. In particular it is about how the actions of children are connected to the histories of their families, and how the privileging of ideas is connected to that of people, and how the practice of science is connected to that of discrimination. Science education reformers may underestimate the difficulty of separating conceptual conflict about ideas from interpersonal conflict about privilege and status. © 2002 Wiley Periodicals, Inc.Sci Ed86:287–313, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/sce.10009
Reforming primary science assessment practices: A case study of one teacher's professional development through action research
Authors: Briscoe Carol , Wells Elaine
Published: August 2002

Calls for reform have suggested that classroom practice can best be changed by teachers who engage in their own research. This interpretive study examines the process of action research and how it contributes to the professional development of a first‐grade teacher. The purpose of the study was to explore the research process experienced by the teacher as she examined whether portfolios could be used as an effective means for facilitating and assessing young children's development of science process skills. Data sources included a journal kept by the teacher, documents produced by the teacher and students as part of the portfolio implementation process, hand‐written records of teacher's informal interviews with students, and anecdotal records from research team meetings during the study. Data analysis was designed to explore how the teacher's classroom practices and thinking evolved as she engaged in action research and attempted to solve the problems associated with deciding what to assess and how to implement portfolio assessment. We also examined the factors that supported the teacher's learning and change as she progressed through the research process. Data are presented in the form of four assertions that clarify how the action research process was influenced by various personal and contextual factors. Implications address factors that facilitated the teacher as researcher, and how this research project, initiated by the teacher, affected her professional development and professional life. © 2002 Wiley Periodicals, Inc.Sci Ed86:417–435, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/sce.10021
Atheoretical nature of the national science education standards: There's more theory than we think—a response to Thomas Shiland
Authors: Pushkin Dave
Published: August 2002

This article seeks to address concerns Shiland raised in his prior article (Science Education 1998, 82(5), 615–617) regarding the National Science Education Standards (NSES). While there is considerable merit to Shiland's article, especially regarding the broadness and lacking specificity of these standards, there are also points to contend. In addition to addressing the pros and cons of the NSES, I will also address how Shiland may have overlooked a more fundamental issue for debate. Three key “failures” Shiland notes of the NSES are more reflective of a possible desire to move away from specific outcomes‐based objectives and towards more global, interdisciplinary learning; these are “failures” only in the eyes of positivistic epistemologies. As for the consequences Shiland foresees, science educators need to get past such consequences by not underestimating the cognitive abilities of classroom teachers and students alike. © 2002 Wiley Periodicals, Inc. Sci Ed 86:161–166, 2002; DOI 10.1002/sce.10027
Reply to Pushkin
Authors: Shiland Thomas W.
Published: August 2002

This comment is in response to Pushkin's critique (Science Education 2002, 86, 161–166) of my original article (Science Education 1998, 82, 615–617). The three aspects of the atheoretical nature of the National Science Education Standards (NSES) from the 1998 article are reviewed in light of Pushkin's comments. This response maintains that it is difficult to achieve scientific literacy without mentioning specific scientific theories and it is difficult to achieve progress in pedagogy without articulating specific theories of instruction and learning. © 2002 Wiley Periodicals, Inc. Sci Ed 86:167–170, 2002; DOI 10.1002/sce.10028
Constructing difference: A comparative study of elementary science curriculum differentiation
Authors: Hayes Michael T. , Deyhle Donna
Published: August 2002

The research described in this article was a comparative study of science curriculum differentiation at two elementary schools that served students from different socioeconomic and ethnic backgrounds. Two schools in the same school district, Lake and Jefferson, were the sites for the research. Lake Elementary served a professional class and white neighborhood, but Jefferson Elementary served students from working‐class/working poor and ethnically diverse backgrounds. The teachers and students in a fifth and sixth grade classroom at each school participated in the research. Research methods drew from ethnographic and linguistic traditions and focused on the microlevel everyday classroom interactions in which the curriculum is constructed. The results of the study show that the science curriculum was quite different between the two schools. The science curriculum at Lake emphasized organization and control for the purpose of preparing students for traditional notions of academic success and progress. At Jefferson, the science curriculum was constructed within an informal and conversational format in an effort to engage students in science. We suggest that it is difficult to determine if and how this curriculum differentiation might establish or enhance inequality in science education. Instead, we offer competing interpretations of the results that draw from current notions of best practice in the science education community. © 2001 John Wiley & Sons, Inc. Sci Ed 85:239–262, 2001.
Region extraction using competition of multiple active contour models
Authors: Matsuzawa Yuki , Abe Toru
Published: August 2002

In most region extraction methods using the Active Contour Model (ACM, Snakes), the entire area of a target object is treated as a single region, and an ACM is deformed locally by image properties around the contour. For these reasons, it is difficult for these methods to extract accurately an object area that has intricate distributions of image properties. In response to this difficulty, to introduce wide‐ranging image properties into the extraction process, it has been proposed to control an ACM by the statistical characteristics of image properties in the object and background regions. However, this approach is unsuitable when image properties vary widely with location in each region. In this paper, to overcome this problem, a novel region extraction method is proposed. The proposed method makes multiple ACMs compete with each other and each ACM extract a subregion of uniform image properties, and, as a result, the method extracts the entire area of an object as a set of several subregions. In the proposed method, first, a few initial curves are set in the object and background regions. Each initial curve is divided into several segments, and multiple initial ACMs are made by dilating these segments. Second, at each ACM, the density function of image properties is estimated, and for each control point on a contour, the likelihood with respect to every ACM region is determined. Based on this likelihood, each ACM is controlled and multiple ACMs compete with each other. © 2001 Scripta Technica, Syst Comp Jpn, 32(5): 1–11, 2001
Tracking a person with 3D motion by integrating optical flow and depth
Authors: Okada Ryuzo , Shirai Yoshiaki , Miura Jun , Kuno Yoshinori
Published: August 2002

In this paper, a method of tracking a person in three‐dimensional motion by integration of optical flow and depth is described. Using a human model, the objective is estimation of the state (position, posture, and motion) in a scene at each frame. Based on the distribution of the estimated state, the optical flow and the depth information are used to calculate the probability of each pixel belonging to the target object, from which the object region is estimated. The optimum state is estimated by integration of the shape, the position, the flow vectors, and the depth information with respect to the extracted target region by a Kalman filter. Because of the nonlinear relation between the state and the shape of the target object on the image, there are cases where the state cannot be determined uniquely. In such situations, the possible candidates are all generated and are tracked one by one. Based on the difference between the tracking results and the observations, the erroneous candidates are eliminated. The effectiveness of the method is shown by its application to real image examples. © 2001 Scripta Technica, Syst Comp Jpn, 32(7): 29–38, 2001
Using ATPG vectors for BIST test pattern generator
Authors: Asakawa Takeshi , Iwasaki Kazuhiko
Published: August 2002

As a solution to improve the characteristics of pseudo‐random pattern tests, a BIST‐oriented test pattern generator (TPG) designed to achieve complete coverage of stuck‐at faults with short test sequences is proposed. In the proposed method, ATPG vector sets are split‐shifted to obtain pseudo‐random vectors, and such vectors are then used in a mixed test pattern. Since random pattern resistant faults are detected by ATPG vectors, stuck‐at faults can be covered completely with a short test sequence. This paper presents the proposed TPG configuration, test pattern generation algorithm, and the selection of the vector set for bit shift. The proposed method is evaluated in terms of test length and hardware overhead by applying it to ISCAS benchmark circuits. © 2001 Scripta Technica, Syst Comp Jpn, 32(11): 1–8, 2001
User interface providing support for creating artistic patterns
Authors: Ichino Junko , Tano Shun'ichi
Published: August 2002

As design work using computer spreads, usage environments are appearing which have operations involving aesthetic sensibilities via the GUIs in a variety of graphics software and have the representational capacity to represent three‐dimensional images and images with the feel of oil paintings. However, their operation still relies on the user's sensibilities and knowledge. In this paper, we propose a user interface for a user support system for creating artistic patterns. Its features are summarized by the following three points. First, the system has knowledge about designs. The result of design analysis provided the following knowledge. (1) The elements producing a design are the colors, shapes, and composition. (2) To turn an image into a pattern, the image is conceived of as a specific scene, then the pattern can be drawn by extracting the colors, shapes, and composition based on the scene by combining these elements. This knowledge is held in the system. Second, there is a user interface to easily transmit the image to the system. The media to convey kansei (affective information) are considered to be both linguistic and nonlinguistic. And an interface was designed to enable direct manipulation by pen or mouse to select from a list box of a three‐level kansei language and to select from a pattern candidate group. Another user interface was designed which accounts for the inability of a person to grasp the kansei from the start to completion and allows repeating the kansei specification by the user and the presentation of patterns by the system. Third, there is a mechanism that automatically creates the pattern in response to the user's kansei. We designed an algorithm to create a design by (1) using fuzzy logic to deduce the user's image and (2) creating the pattern by using the parameters needed to draw the pattern which were extracted from the deduced image. Furthermore, we developed a support system for creating artistic patterns that has the above functions, and had multiple testers test its operation to verify the system's effectiveness in application tests on real problems. © 2001 Scripta Technica, Syst Comp Jpn, 32(11): 20–37, 2001
Piecewise linear two‐dimensional warping
Authors: Uchida Seiichi , Sakoe Hiroaki
Published: August 2002

As a novel elastic image matching technique, piecewise linear 2D warping (PL2DW) is investigated. In PL2DW, the mapping of each row of one image to another image is given by the linear interpolation of the mapping of several points, called pivots, prepared on the row. The linearization realizes a dynamic programming (DP)‐based algorithm with feasible computational complexity, although many DP‐based algorithms for elastic image matching are intractable. Experimental results show the effectiveness, and particularly the computational feasibility, of PL2DW. © 2001 Scripta Technica, Syst Comp Jpn, 32(12): 1–9, 2001
A nonscan DFT method for controllers to provide complete fault efficiency
Authors: Ohtake Satoshi , Masuzawa Toshimitsu , Fujiwara Hideo
Published: August 2002

In this paper, we propose a method for non‐scan design for testability of controllers that are logically synthesized from a finite state machine (FSM), which provides complete fault efficiency. In the previously used scan method, a test pattern for the combinational circuits of a controller was generated to achieve complete fault efficiency and was applied by using a scan flip‐flop. However, in the scan method, the test sequence becomes large and various problems prevent the test from being performed at the actual operating speed. In this paper, the test pattern of the combinational circuits of the controller does not use scan flip‐flops, but instead uses the state transitions of an FSM. The proposed method allows performance of the test at the actual operating speed of the circuit, thus reducing the testing time compared to the conventional methods. Moreover, experimental results using benchmarks show that the area overhead is small. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(5): 64–75, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1128
Energy shift and broadening of the spectra of electrons backscattered elastically from solid surfaces
Authors: Varga D. , Tőkési K. , Berényi Z. , Tóth J. , Kövér L. , Gergely G. , Sulyok A.
Published: August 2002

In the present work our experimental results on the energy shifts and energy widths (full width of half‐maximum) of the quasi‐elastic peaks (1–5 keV) obtained using a high‐energy‐resolution electron spectrometer and different (C, Si, Ni and Au) surfaces are compared with those calculated by assuming single elastic scattering on free atoms having a Maxwell–Boltzmann thermal velocity distribution. There is a good agreement in the case of the energy shifts as well as for the energy broadenings obtained using higher atomic number polycrystalline samples (Ni, Au). In the case of Si, however, the measured energy broadening is systematically larger by 15–20% than the calculated broadening for the whole primary beam energy range. Compared with the calculated values, considerably larger broadenings (by 30–60%, depending on the primary beam energy) were observed for carbonic samples. The contribution of the multiple elastic scattering to the yield of the electrons backscattered elastically, and the effect of the multiple scattering on the energy shifts and Doppler broadenings, have been determined using Monte Carlo simulations. Our results show that multiple scattering causes only small changes in energy shifts and energy broadenings of elastic peaks in the case of the samples and primary electron energy region studied. Copyright © 2001 John Wiley & Sons, Ltd.
Summary of ISO/TC 201 Technical Report: ISO/TR 15969:2000—Surface chemical analysis—Depth profiling—Measurement of sputtered depth
Authors: Hofmann S.
Published: August 2002

This Technical Report gives guidelines for the measurement of the sputtered depth in sputter depth profiling. Methods of sputtered depth measurement described in this report are applicable to techniques of surface chemical analysis when used in combination with ion bombardment for the removal of a part of a solid sample to a typical sputtered depth of up to several micrometres. Copyright © 2002 John Wiley & Sons, Ltd.
Competing approaches to analysis of failure times with competing risks
Authors: Farley Timothy M. M. , Ali Mohamed M. , Slaymaker Emma
Published: August 2002

For the analysis of time to event data in contraceptive studies when individuals are subject to competing causes for discontinuation, some authors have recently advocated the use of the cumulative incidence rate as a more appropriate measure to summarize data than the complement of the Kaplan–Meier estimate of discontinuation. The former method estimates the rate of discontinuation in the presence of competing causes, while the latter is a hypothetical rate that would be observed if discontinuations for the other reasons could not occur. The difference between the two methods of analysis is the continuous time equivalent of a debate that took place in the contraceptive literature in the 1960s, when several authors advocated the use of net (adjusted or single decrement life table rates) rates in preference to crude rates (multiple decrement life table rates). A small simulation study illustrates the interpretation of the two types of estimate – the complement of the Kaplan–Meier estimate corresponds to a hypothetical rate where discontinuations for other reasons did not occur, while the cumulative incidence gives systematically lower estimates. The Kaplan–Meier estimates are more appropriate when estimating the effectiveness of a contraceptive method, but the cumulative incidence estimates are more appropriate when making programmatic decisions regarding contraceptive methods. Other areas of application, such as cancer studies, may prefer to use the cumulative incidence estimates, but their use should be determined according to the application. Copyright © 2001 John Wiley & Sons, Ltd.
Prospective application of Bayesian monitoring and analysis in an ‘open’ randomized clinical trial
Authors: Vail A. , Hornbuckle J. , Spiegelhalter D. J. , Thornton J. G.
Published: August 2002

We describe the prospective application of Bayesian monitoring and analysis in an ongoing large multi‐centre, randomized trial in which interim results are released to investigators. Substantial variability in prior opinion led us to reject the use of elicited clinical priors for monitoring, in favour of archetypal prior distributions representing reasonable scepticism and enthusiasm. Likelihoods for odds ratios for different covariate values are derived from a logistic regression model, which allows us to incorporate information from prognostic factors without resorting to specialized software. Priors, likelihoods and posterior distributions are regularly reported to both an independent Data Monitoring Committee and the trial investigators. Copyright © 2001 John Wiley & Sons, Ltd.
The sample size for a clinical trial: A Bayesian–decision theoretic approach
Authors: Halpern Jerry , Brown Byron Wm. , Hornberger John
Published: August 2002

Using decision theory, what is an appropriate sample size for a clinical trial, with a binary endpoint? We present a program, suitable for actual planning, which, with some extensions, implements Canner's solution to this question. Examples with a discussion are given. Implications of a Bayesian approach are discussed. Bayesian and Neyman–Pearson approaches are compared. Copyright © 2001 John Wiley & Sons, Ltd.
Statistical measures of foetal growth using linear mixed models applied to the foetal origins hypothesis
Authors: Gurrin Lyle C. , Blake Kevin V. , Evans Sharon F. , Newnham John P.
Published: August 2002

Statistical models of the relationship between the distribution of each of five foetal dimensions and gestational age are developed based on serial ultrasound biometric data from a prospective longitudinal study in Perth, Western Australia. Both the response variable and the gestational age timescale are transformed to establish an approximately linear relationship within subjects. This relationship is modelled using a linear mixed effects model that accounts for between‐subject heterogeneity by incorporating subject specific random effects for both intercept and gradient. These models are used to motivate three measures of foetalgrowth: the conditional centile orz‐score of a current measurement given an earlier value for the same measurement; the best linear unbiased predictor (BLUP) of the subject specific random effect gradient (which is shown to be invariant to transformations of location and scale), and the standardized residual at a given gestational age, which characterizes departures from the modelled growth trajectory. We illustrate how these three measures of growth might be applied to subsequent health outcomes in later life by relating growth in foetal abdominal circumference to blood pressure in children from the same cohort at six years of age. Foetuses whose summary measures indicate poor growth in abdominal circumference have higher blood pressure in early childhood, supporting the ‘foetal origins’ hypothesis that many chronic diseases of adulthood have their origins before birth. Copyright © 2001 John Wiley & Sons, Ltd.
A comparison of methods for adaptive sample size adjustment
Authors: Friede Tim , Kieser Meinhard
Published: August 2002

In fixed sample size designs, precise knowledge about the magnitude of the outcome variable's variance in the planning phase of a clinical trial is mandatory for an adequate sample size determination. Wittes and Brittain introduced the internal pilot study design that allows recalculation of the sample size during an ongoing trial using the estimated variance obtained from an interim analysis. However, this procedure requires the unblinding of the treatment code. Since unblinding of an ongoing trial should be avoided whenever possible, there should be some benefit of this design compared with blinded sample size recalculation procedures to justify the unveiling of the treatment code. In this paper, we compare several sample size recalculation procedures with and without unblinding. The simulation results indicate that the procedures behave similarly. In particular, breaking of the blind is not required for an efficient sample size adjustment. We also compare these pure sample size adaptation procedures with study designs which additionally allow for early stopping. Evaluation of the cumulative distribution function of the resulting sample sizes shows that the option for early stopping may lead to lower expectation but generally to a higher variability. The procedures are illustrated by an example of a trial in the treatment of depression. Copyright © 2001 John Wiley & Sons, Ltd.
Analysis of ulcer data using hierarchical generalized linear models
Authors: Lee Youngjo , Nelder John A.
Published: August 2002

In multi‐centre clinical trials, heterogeneities in individual hospital treatment effects can be modelled as random effects. Estimates of the individual hospital treatment effects and estimate of the mean treatment effect, allowing for the presence of overall hospital differences, are required, together with some measure of their uncertainty. Systematic inferences from the hierarchical‐likelihood are now possible, using hierarchical generalized linear models. We show how to construct profile likelihoods for the treatment effects of individual hospitals. Copyright © 2002 John Wiley & Sons, Ltd.