bluuebunny/crossref_metadata_2025 huggingface dataset:
Synergistic Effects of Multiple Metal Contaminants on Electrokinetic Remediation of Soils
Authors: Reddy Krishna R. , Chinthamreddy Supraja , Al‐Hamdan Ashraf
Published: August 2002

This article presents a bench‐scale study performed to investigate the removal of heavy metals when
they exist individually and in combination in soils. Electrokinetic experiments were conducted using two types
of clayey soils, kaolin and glacial till. These soils were contaminated with Cr(VI) only, with
Ni(II) only, and with Cr(VI), Ni(II), and Cd(II) combined. It was found
that in kaolin, a significant pH variation occurred due to electric potential application, affecting the
adsorption‐desorption and dissolution‐precipitation, as well as the extent of migration of the
contaminants. In glacial till, however, pH changes were not affected significantly. In both kaolin and glacial
till, the migration of Cr(VI) and Ni(II) was higher when they were present individually
compared to when they existed together with Cd(II). Cr(VI) migration as single or combined
contaminant was lower in kaolin as compared to that in glacial till. This result was due to the low pH
conditions created near the anode region in kaolin that led to high Cr(VI) adsorption to the clay
surfaces. In glacial till, however, nickel precipitated with or without the presence of co‐contaminants
due to high pH conditions in the soil. Overall, this study demonstrates that adsorption, precipitation, and
reduction are the significant hindering mechanisms for the removal of heavy metals using electrokinetic
remediation. The direction of the contaminant migration and overall removal efficiency depend on the polarity of
the contaminant, the presence of co‐contaminants, and the type of soil. © 2001 John Wiley &
Sons.
Receptor for the group B coxsackieviruses and adenoviruses: CAR
Authors: Carson Steven D.
Published: August 2002

Considerable progress towards the characterisation of the long‐sought receptor, CAR (coxsackievirus and adenovirus receptor), shared by group B coxsackieviruses (CVB) and most adenoviruses (Ad) has been made since it was isolated and cloned in 1997. The primary sequence of CAR shows that it is a member of the immunoglobulin superfamily of proteins, containing two Ig superfamily domains: an amino‐terminal V‐like module and a C2‐like module. The CAR cytoplasmic domain, representing nearly one‐third of the protein, is separated from the C2‐like module by a single membrane‐spanning sequence. The structure of the CAR V‐like module complexed with the Ad fibre knob has been determined using recombinant proteins, and reveals three CAR modules associated with a single knob. Although recombinant CAR expressed in mammalian cells confers permissivity to CVB infection, details of the interaction between CAR and CVB remain to be elucidated. The expression of CAR appears to be highly regulated with respect to both cell type and developmental age. In rodents, CAR is expressed at high levels just before birth, and declines thereafter. Expressed levels have been found to increase in regenerating muscle and in response to immunological mediators or inflammation, and in RD cells and umbilical vein endothelial cells in response to high cell density. These studies indicate that CAR expression is highly regulated, but the mechanisms and molecules that mediate the expression remain to be discovered. The physiological function of CAR and its natural ligand also remain to be discovered. In addition, while CAR expression generally correlates with viral tropism, the relationship between the physiological function of CAR and the pathologies of CVB and Ad infections remain to be described. Copyright © 2001 John Wiley & Sons, Ltd.
Hepatitis B and hepatitis C co‐infection in patients with HIV. Reviews in Medical Virology 11(4): 253‐270
Authors: Martinez E. Herrero
Published: August 2002

The original article to which this Erratum refers was published in Reviews in Medical Virology 11(4): 253‐270
Asymptotic output tracking of a class of nonlinear systems by means of an observer
Authors: Martínez‐Guerra Rafael , Suarez Rodolfo , León‐Morales Jesús De
Published: August 2002

An observer‐based controller strategy for the asymptotic output tracking of a class of nonlinear systems is proposed. The generalized observability canonical form (𝒢𝒪𝒞ℱ) introduced by Fliess, is the main ingredient in our approach. Our tracking controller actually achieves uniform asymptotic stability by linearizing the tracking error. Two examples are considered to illustrate the effectiveness of the suggested approach. Copyright © 2001 John Wiley & Sons, Ltd.
Stabilization of invariant tori in Hamiltonian systems under persistently acting disturbances
Authors: Polushin Ilya G.
Published: August 2002

The problem of invariant tori stabilization in multi‐degrees‐of‐freedom Hamiltonian systems under uniformly bounded disturbances is considered. The main result gives the conditions for ultimate boundedness of trajectories of controlled system under disturbances with respect to the torus to be stabilized. The estimates for region of attraction and ultimate bound are obtained. The essential role in the proof is played by Lemma 1, which gives the conditions for ultimate boundedness with respect to a given nonnegative smooth functionVwithout assumption of negative (semi)‐definiteness of time derivative ofV. Copyright © 2001 John Wiley & Sons, Ltd.
DC‐to‐AC power conversion on a ‘boost’ converter
Authors: Sira‐Ramírez Hebertt
Published: August 2002

In this article, we provide an approximate sliding mode control‐based solution to the DC–AC power conversion problem on a ‘boost’ converter. The approach uses the flatness property of the system as a pivot for generating a sequence of minimum phase output reference trajectory candidates. The generated candidates are obtained as differential parameterizations of the minimum phase inductor current variable in terms of the non‐minimum phase desired output capacitor voltage. The associated residual dynamics of the ideal sliding motions is shown to reasonably approximate the desired biased sinusoidal output capacitor voltage signal. Copyright © 2001 John Wiley & Sons, Ltd.
Set membership localization and mapping for autonomous navigation
Authors: Di Marco M. , Garulli A. , Lacroix S. , Vicino A.
Published: August 2002

In this paper a set theoretic estimation approach is proposed for dynamic localization problems in the area of mobile robot autonomous navigation. Self‐localization of mobile robots is one of the most important problems in long range autonomous navigation. When moving in an unknown environment, the navigator must exploit measurements from exteroceptive sensors to build a map, identify landmarks and, at the same time, localize itself with respect to them. This problem is known as simultaneous localization and mapping (SLAM).

Under the hypothesis that the errors affecting all sensor measurements are unknown but bounded, set membership techniques, successfully employed in the robust identification area of research, are exploited to devise procedures for guaranteed estimation of robot and landmarks positions in terms of uncertainty regions. Set approximation is adopted in order to provide efficient recursive algorithms, suitable for on‐line implementation. Copyright © 2001 John Wiley & Sons, Ltd.
Idle speed control of a direct injection spark ignition stratified charge engine
Authors: Grizzle J. W. , Buckland Julia , Sun Jing
Published: August 2002

Idle speed control is investigated for a direct injection, spark ignition, stratified charge (DISC) engine equipped with an electronic throttle. Such engines can be operated in multiple combustion modes. When operating in stratified charge combustion mode, they are very different from conventional stoichiometric engines, creating new opportunities for improved speed control. With current after‐treatment technology, simultaneous high fuel economy and emissions conversion efficiency cannot be achieved by operating the engine in a steady‐state manner: it must be cycled between running ultra‐lean (for fuel economy) and rich (to service the after‐treatment system). An idle speed control system is designed to meet the considerable feedback control demands required by these new engines. Copyright © 2001 John Wiley & Sons, Ltd.
Design of full state feedback finite‐precision controllers
Authors: D'Andrea Raffaello , Istepanian Robert S. H.
Published: August 2002

In this paper, the Generalized L2 Synthesis framework is brought to bear on the problem of control design of full state feedback finite‐precision controllers. In particular, we investigate the problem of designing full state feedback controllers that achieve guaranteed H‐infinity performance objectives, subject to finite precision constraints on the controller. It is shown that by adopting the Generalized L2 Synthesis framework, the errors in the controller implementation can be captured as full structured uncertainty, and computationally tractable linear matrix inequality techniques used for analysis and synthesis. Copyright © 2002 John Wiley & Sons, Ltd.
The kinematics for redundantly actuated omnidirectional mobile robots
Authors: Yi Byung‐Ju , Kim Whee Kuk
Published: August 2002

Omnidirectional mobile robots have been popularly employed in several application areas. However, the kinematics and singularity analysis for these systems have not been clearly identified, especially for the redundantly actuated case, which is common in current omnidirectional mobile robots. In light of this fact, this article introduces two different kinematic approaches for a typical omnidirectional mobile robot having three caster wheels, and examines singularity configurations of such systems. Then, a singularity‐free load‐distribution scheme for a redundantly actuated three‐wheeled omnidirectional mobile robot is proposed. Through simulation, several advantages of the redundantly actuated mobile robot (singularity avoidance, input‐load saving, and exploiting several subtasks) are presented. © 2002 Wiley Periodicals, Inc.
Minimal realizations of spatial stiffnesses with parallel or serial mechanisms having concurrent axes
Authors: Huang Shuguang , Schimmels Joseph M.
Published: August 2002

This article presents a new method for the synthesis of an arbitrary spatial elastic behavior with an elastic mechanism. The mechanisms considered are parallel and serial mechanisms with concurrent axes. We show that any full‐rank spatial stiffness matrix can be realized using a parallel mechanism with all spring axes intersecting at a unique point. It is shown that this intersection point must be the center of stiffness. We also show that any full‐rank spatial compliance matrix can be realized using a serial mechanism with all joint axes intersecting at a unique point. This point is shown to be the center of compliance. Synthesis procedures for mechanisms with these properties are provided. The realizations are shown to be minimal in the sense that both the number of screw components and the total number of components are minimum. © 2001 John Wiley & Sons, Inc.
The dexterity and singularities of an underactuated robot
Authors: Roberts Rodney G.
Published: August 2002

Underactuated robots are robotic systems with more joints than actuators. A robot may be underactuated by design as in the case of a hyper‐redundant robot with passive joints or may become underactuated as a result of an actuator failure. In this article, we examine the dexterity of underactuated robots whose passive joints operate in either a locked or free‐swinging mode. The ability to an analyze the dexterity of an underactuated robot has important applications especially for the control of passive joints with brakes and for the fault tolerance analysis of an otherwise fully actuated kinematically redundant robot. The approach applied here is to use kinematics and dynamics‐based formulations of manipulator dexterity. We then characterize passive‐joint singularities, i.e., configurations where full end‐effector control is lost because one or more joints are passive instead of active. Lastly, we introduce a new characterization of joint‐limit singularities, which are configurations where full end‐effector control cannot be achieved because one or more joints are at their joint limits. © 2001 John Wiley & Sons, Inc.
Manipulating deformable linear objects: Attachable adjustment‐motions for vibration reduction
Authors: Yue Shigang , Henrich Dominik
Published: August 2002

This paper addresses the problem of handling deformable linear objects in a suitable way to avoid acute vibration. Different types of adjustment‐motions that eliminate vibration of deformable objects and that can be attached to the end of an arbitrary end‐effector's trajectory are presented. For describing the dynamics of deformable linear objects, the finite element method is used to derive the dynamic differential equations. A genetic algorithm is used to find the optimal adjustment motion for each simulation example. Experiments are conducted to verify the presented manipulating method. © 2001 John Wiley & Sons, Inc.
Using OXSIMfor path planning
Authors: Cameron Stephen , Pitt‐Francis Joe
Published: August 2002

We address the issue of building scalable and reusable path planners for realistic robot manipulators working in three‐dimensional space amid complex geometry, by presenting the latest version of our robot manipulator planning toolbox, OxSIM. OxSIMis designed to greatly simplify the building of planners by providing core competence in three‐dimensional geometry. This is done by the provision of efficient routines for computing the distance between parts of the robot and its environment. A new version of OXSIM, written in C++, provides an object‐oriented interface to the basic system, which increases its ease of use. Here we give an overview of OxSIMand how it works and describe a modified version of the probabilistic road map planner that we have implemented under the framework. © 2001 John Wiley & Sons, Inc.
MPK: An open extensible motion planning kernel
Authors: Gipson Ian , Gupta Kamal , Greenspan Michael
Published: August 2002

The motion planning kernel (MPK) is a software system designed to facilitate development, testing, and comparison of robotic and geometric reasoning algorithms. Examples of such algorithms include automatic path planning, grasping, etc. The system has been designed to be open and extensible, so that new methods can be easily added and compared on the same platform. © 2001 John Wiley & Sons, Inc.
An evolutionary and local search algorithm for motion planning of two manipulators
Authors: Ridao M. A. , Camacho E. F. , Riquelme J. , Toro M.
Published: August 2002

A method for obtaining coordinated motion plans of robot manipulators is presented. A decoupled planning approach has been used; that is, the problem has been decomposed into two subproblems: path planning, where a collision‐free path is found for each robot independently only considering fixed obstacles, and trajectory planning, where the paths are timed and synchronized to avoid collisions with other robots. This article focuses on the second problem. The proposed plan can easily be implemented by programs written in most industrial robot programming languages. The generated programs minimize the total motion time of the robots along their paths. The method does not require accurate dynamic models of the robots and uses an evolutionary algorithm followed by a local search which produces near optimal solutions with a relatively small computational cost. © 2001 John Wiley & Sons, Inc.
A novel adaptive bilateral control scheme using similar closed‐loop dynamic characteristics of master/slave manipulators
Authors: Ryu Jee‐Hwan , Kwon Dong‐Soo
Published: August 2002

This article presents a novel adaptive bilateral control scheme for obtaining ideal responses for teleoperation systems with uncertainties. A condition that is equivalent to getting an ideal response in teleoperation has been found to be making the closed‐loop dynamics of master and slave manipulators a similar form. An adaptive approach is applied to achieve similarity for the uncertain master and slave manipulators. Using the similar closed‐loop dynamic characteristics of master/slave teleoperation systems, excellent position and force tracking performance has been obtained without estimating the impedance of human and environment. The validity of the theoretical results is verified by experiments. © 2001 John Wiley & Sons, Inc.
When does a robot perceive a dynamic object?
Authors: Krishna K. Madhava , Kalra Prem K.
Published: August 2002

Robots operating in a real‐time environment encounter both stationary and moving objects that need to be
negotiated using different schemes in general. Motion planning in a dynamic environment entails tracking moving
objects and predicting their future positions. However, this requires as a first step the classification of the
objects present in the environment as static or dynamic objects, a step that somehow seems to have been overlooked
in the literature dealing with navigation in dynamic environments. Presented here are four schemes for perceiving
the presence of dynamic objects in the robot's neighborhood. The first approach incorporates a network
architecture that classifies the robot's experience of the environment in terms of spatio‐temporal
sensor patterns as an experience of a static or dynamic object. The second method detects motion by observing
changes in the map of the environment it builds and updates. The remaining two approaches use a strategy for
representing the objects in the environment through clusters; inspecting the characteristics of the clusters
reveals the dynamic objects. These methods are denoted as STA (spatio‐temporal approach), MBA
(model‐based approach), and CBAI and CBAII (cluster‐based approach I and II),
respectively. The methods have been tested in environments that contain multiple dynamic objects amidst static
ones and their efficacy established. A brief comparison of these approaches in terms of criteria critical for
real‐time collision avoidance has also been presented. © 2002 John Wiley & Sons, Inc.
Real‐time actual pose determination of the general fully parallel spherical wrist, using only one extra sensor
Authors: Parenti‐Castelli Vincenzo , Di Gregorio Raffaele
Published: August 2002

The direct position analysis of the fully parallel spherical wrist with general geometry can have up to eight poses for a given set of leg lengths. This paper presents a procedure that makes use of one extra rotary sensor, suitably located in the wrist (in addition to the three linear sensors embedded in the leg servosystems) to enable the actual pose of the spherical wrist to be uniquely defined and the wrist direct position analysis to be computed in real time. Closed‐form solution of the direct position analysis is obtained, which makes it possible to refine the measurement provided by the extra sensor and consequently to improve the robustness of the procedure. Examples are reported that show the efficiency of the procedure. © 2001 John Wiley & Sons, Inc.
A general solution for the position, velocity, and acceleration of hyperredundant planar manipulators
Authors: Asl Farshid Maghami , Ashrafiuon Hashem , Nataraj C.
Published: August 2002

A new approach for the solution of the position, velocity, and acceleration of hyperredundant planar manipulators following any twice‐differentiable desired path is presented. The method is singularity free, and provides a robust solution even in the event of mechanical failure of some of the robot actuators. The approach is based on defining virtual layers, and dividing them into virtual/real three‐link or four‐link subrobots. It starts by solving the inverse kinematic problem for the subrobot located in the lowest virtual layer, which is then used to solve the inverse kinematic equations for the subrobots located in the upper virtual layers. An algorithm is developed that provides a singularity‐free solution up to the full extension through a configuration index. The configuration index can be interpreted as the average of the determinants of the Jacobians of the subrobots. The equations for the velocities and accelerations of the manipulator are solved by extending the same approach, and it is shown that the value of the configuration index is critical in maintaining joint velocity continuity. The inverse dynamic problem of the robot is also solved to obtain the torques required for the robot actuators to accomplish their tasks. Computer simulations of several hyperredundant manipulators using the proposed method are presented as numerical examples. © 2002 John Wiley & Sons, Inc.
The significance of flood regimes for carabid beetle and spider communities in riparian habitats—a comparison of three major rivers in Germany
Authors: Bonn Aletta , Hagen Katja , Reiche Dagmar Wohlgemuth‐von
Published: August 2002

River regulation and water management practices have led to alteration of the flood regimes of all large rivers in Germany. To investigate its influence on the terrestrial arthropod fauna, a comparative study was carried out on the distribution of ground beetles (Carabidae) and spiders (Araneae) at the potamal sections of three large rivers in northern Germany, the Rivers Weser, Elbe and Oder. The three rivers differ markedly in their flood dynamics, mainly owing to weirs and polder management practices, but also owing to natural conditions in their headwaters. In total, 45 sites were examined with a total capture of 46 727 carabid beetles and 38 066 adult spiders, representing 178 and 209 species, respectively. Using multivariate TWINSPAN analyses we found that the ground beetle species assemblages clearly varied according to the different flood regimes. By contrast, the spiders differentiate well between sites of different habitat structure.

In particular, the river margins hosted a specialized carabid fauna, and the alluvialQuercus–Ulmusforests were habitat for some rare and endangered carabid and spider species. Whereas the fauna of the strongly regulated River Weser was impoverished regarding stenotopic hygrophilous species, the fauna of the more natural Rivers Elbe and Oder depended very much on the duration and timing of the flooding, as well as on the local micro‐topographical situation. It is concluded that low lying areas behind dykes of the Elbe, or in polders of the Oder, which become frequently inundated by river or ground water, are extremely valuable for invertebrate conservation. The data suggest that careful polder management may support suitable habitat creation for riparian species, as long as the inundation scheme corresponds to natural flood dynamics conditions. Copyright © 2002 John Wiley & Sons, Ltd.
On probabilistic elimination of generalized quantifiers
Authors: Kaila Risto
Published: August 2002

Let 𝒬 be a collection of generalized quantifiers. We give a convenient characterization for the cases where the logic ℒ︁(𝒬) has quantifier elimination for an arbitrary class of structures. The results provide a method to prove zero‐one and convergence laws for such logics with arbitrary sequences of probability measures of finite structures. © 2001 John Wiley & Sons, Inc. Random Struct. Alg., 19, 1–36, 2001
Physical–statistical methods for determining state transition probabilities in mobile‐satellite channel models
Authors: Saunders S. R. , Tzaras C. , Evans B. G.
Published: August 2002

Signal propagation in land mobile satellite (LMS) communication systems has for the last decade become an essential consideration, especially when high‐rate data services are involved. As far as urban or suburban built‐up areas are concerned, the extent of the influence is mainly restricted to the roadside obstacles, since the satellite is positioned at relatively high elevation angles in most practical situations. Probably, the most common model currently used for representing the LMS channel is the Lutz model, which uses two states to represent line‐of‐sight and non‐line‐of‐sight conditions. Transitions between these states are described by transition probabilities which are a function of the environment and the satellite elevation angles. Similarly, an extension to the model allows a four‐state description to be used for the states associated with a pair of satellites used in a dual‐diversity configuration. Calculation of the transition probabilities then requires knowledge of the correlation between the two channels, which in turn depends on the spatial characteristics of the local environment around the mobile.

In both cases, the transition probabilities have been derived basically from measurements in the past. In the new approaches described in this paper, physical–statistical principles are applied to construct analytical formulas for the probabilities of shadowing and the correlation between states. These expressions apply particularly to systems operated in built‐up environments, and have been checked against numerical experiments and against direct measurements. In both cases excellent agreement is obtained. Copyright © 2001 John Wiley & Sons, Ltd.
Joint spectrum and power optimization in the design of the UMTS satellite component
Authors: Cianca Ernestina , De Fina Silvia , Ruggieri Marina
Published: August 2002

The paper provides a power and spectrum joint analysis of the universal mobile telecommunications system (UMTS) satellite component, based on the wideband code division multiple access (W‐CDMA) air interface. In fact, power and spectral efficiency may become highly conflicting requirements in a satellite system and a trade‐off analysis is needed to drive a proper dimensioning of the satellite. The proposed approach allows a dimensioning of the satellite component either in terms of orbit and power budget or in terms of additional capacity for the terrestrial section, for specified orbit and power limitations. The impact of candidate frequency bands, orbit type and diversity on both spectral and power requirements of the satellite component is evaluated. For given traffic requirements, power‐vs‐spectrum trade‐off is proposed which ensures a proper resources utilization. The efficiency evaluation accounts for: beams overlapping, ortho gonality, voice activity factor, diversity and cross‐polarization frequency reuse. Perfect power control is assumed and the effect of the excess power required by the shadowed users is accounted for in the interference calculation. Furthermore, still in the frame of a proper resource exploitation, a possible optimization of capacity through the use of unpaired bands in the two link directions is analysed. Copyright © 2001 John Wiley & Sons, Ltd.
Reliable multicast via satellite: a comparison survey and taxonomy
Authors: Koyabe Martin W. , Fairhurst Godred
Published: August 2002

IP multicasting is an important service, which will be provided by the next generation Internet. A range of applications has emerged which take the advantage of multicast delivery. However, several factors currently hinder large‐scale deployment of terrestrial multicast services. It is particularly difficult to support delivery to large groups of users.

Satellites offer a natural way to extend the multicast service to reach this large number of users. They may offer high capacity (especially when using next generation satellite systems) and also eliminate the need for a large number of intermediate routing hops. There are important differences in the way multicast applications operate over satellite. This paper therefore reviews the key design paradigm and offers a critical comparison between different reliable multicast protocol techniques based on a taxonomy. The suitability of a set of the most common reliable multicast protocols is assessed within a satellite environment and conclusions are presented. Copyright © 2001 John Wiley & Sons, Ltd.
TCP‐Peach for satellite networks: analytical model and performance evaluation
Authors: Akyildiz Ian F. , Morabito Giacomo , Palazzo Sergio
Published: August 2002

Current TCP protocols have low throughput performance in satellite networks mainly due to the effects of long propagation delays and high link error rates. TCP‐Peach is a new congestion control scheme for satellite IP networks based on the use of low priority segments, called dummy segments. The sender transmits dummy segments to probe the availability of network resources. Dummy segments are treated as low priority segments thus, they do not effect the throughput of actual data segments. In this paper, TCP‐Peach is presented along with its analytical model which is used to evaluate the throughput performance. Experiments show that TCP‐Peach is robust to high link error rates as well as long propagation delays, and outperforms other TCP schemes for satellite networks. Copyright © 2001 John Wiley & Sons, Ltd.
Shadowing correlation assessment and modeling for satellite diversity in urban environments
Authors: Vazquez‐Castro M. , Perez‐Fontan F. , Saunders S. R.
Published: August 2002

Non‐geostationary orbit satellite networks have dynamic, yet deterministic topologies. This paper deals with the consequences of relying on the use of multiple visible satellites to improve availability with time/locations through satellite diversity techniques. The assumption of independent blockage events in two different satellite‐to‐mobile links is generally not accurate and information on shadowing correlation should be taken into account in the assessment of availability.In this paper a shadowing correlation study for urban environments is presented and a model for the real environments, as well as for a generic urban environment is inferred. The model proposed here is simple and can be run on a computer. It also relates urban and constellation geometries thus allowing the identification of those cases for which satellite diversity gain should be expected. As a result of this analysis and modelling, we present empirical analytical expressions describing positive correlation coefficient as a function of satellite angular separation (azimuth and elevation). We also show that an angle exists above which correlation can be negative and satellite diversity can sensibly improve link availability. Copyright © 2002 John Wiley & Sons, Ltd.
DigitalEE: A support system for collaborative environmental education using distributed virtual space
Authors: Okada Masaya , Yoshimura Tetsuhiko , Tarumi Hiroyuki , Moriya Kazuyuki , Sakai Tetsuro
Published: August 2002

We have developed “DigitalEE,” a system that supports collaborative environmental education via distributed virtual space accessible from real and virtual worlds. With DigitalEE, learners in the real world and environmental specialists in virtual worlds can make interactive communication via “3D virtual nature,” which is a VRML world three‐dimensionally representing real forest, while mutually sharing learners' achievements and environmental specialists' knowledge that are accumulated in common knowledge databases on the server. Our system realizes various unique functions such as accumulation of environmental knowledge derived from real natural experiences, education supported by specialized knowledge of environmental specialists from all over the world, virtual tours to the natural environment that is not easily accessible, and global arguments on environmental issues with worldwide participants. The system aims at enlightening learners' consciousness of environmental preservation by realization of these functions that have been difficult to support with conventional methods in environmental education. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(8): 51–63, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10039
Development of a PC‐based real‐time surgical simulator
Authors: Mukai Nobuhiko , Harada Masayuki , Muroi Katsunobu , Miyamoto Yuji , Uratani Akihiro , Yano Toru
Published: August 2002

Presently, in constructing a surgical simulator, a high‐performance graphics workstation (GWS) has generally been used because it is necessary that a highly faithful surgical image be generated in real time. There exist problems, however, in cost, operation, and working environment, which have prevented the widespread use of the simulator. In order to solve this problem, the authors constructed a real‐time PC‐based surgical simulator for the training of ophthalmologists in vitreoretinal surgery, based on the results of evaluation of a surgical simulator developed on GWS. From this study, the necessary conditions for the simulator have been identified, and a PC‐based surgical simulator satisfying these conditions has been successfully constructed. The constructed system can perform the following operations. The surgical image is displayed in stereo vision, through a binocular stereo vision display. The tactile sensation of surgical tool insertion is provided by using a simulated tool device. The surgery scene can be controlled by operating a foot switch. The constructed surgical simulator provides an environment which effectively simulates real surgery. If an increased number of ophthalmologists can use the proposed simulator more easily for repetitive surgery training, surgical techniques will be improved, and new surgical procedures may be developed. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(7): 11–20, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10076
Measurement of human vocal emotion using fuzzy control
Authors: Moriyama Tsuyoshi , Ozawa Shinji
Published: August 2002

This paper proposes a sentiment measurement system that is based on the relation between speech parameters and included emotion and that is implemented through a learning process using speech data which include known sentiments. In this study, “emotion” and “sentiment” are distinguished in a model of emotional communication by speech which for the first time includes the viewpoint of the observer in addition to those of the speaker and the listener. The sentiment measurement system is constructed by implementing a computational model of the observer. A fuzzy control method is applied in the learning process. The effectiveness of the system is verified by experiments in which the system outputs are compared with psychological evaluations by human subjects. © 2001 Scripta Technica, Syst Comp Jpn, 32(4): 59–68, 2001
The subspace method in Hilbert space
Authors: Tsuda Koji
Published: August 2002

The subspace method has usually been applied to a multidimensional space (i.e., feature space) which uses features as its basis. A subspace method can also be applied to a functional space, since the subspace can be defined by an arbitrary linear space. This paper proposes the mapping of a feature space onto the Hilbert subspace so that pattern recognition can be performed by the subspace method. The proposed method has been experimentally applied to the recognition of the Japanese hiragana syllabary and has achieved a higher recognition rate than the conventional method. This improvement is based on the fact that the dimension of the common part in all of the classes of the subspaces in the Hilbert function space becomes zero. © 2001 Scripta Technica, Syst Comp Jpn, 32(6): 55–61, 2001
Discriminating spinal deformity employing centroids difference on the moiré images
Authors: Kim Hyoung Seop , Ishida Kazufumi , Ishikawa Seiji , Ohtsuka Yoshinori , Shimizu Hisashi
Published: August 2002

Spinal deformities, a condition in which the spine deviates to the left or right from the midline, are on the rise, particularly among elementary and middle‐school students. Group diagnoses are being performed at schools for the purpose of early detection, but the burden on physicians is high due to the need to process many images. Automated diagnosis using computers is highly desirable from the standpoint of treatment. In this paper the authors establish a left–right rectangular processing region in a moiré image of a human back, then propose a method to automatically detect spinal deformities with the differences in the centroid positions as a feature. Using an approximately symmetrical reference axis which closely follows the midline of a person, and the amount of the feature from the centroid position of the left–right rectangular region as centered on the reference axis, the authors' method discriminates between normal cases and abnormal cases using a linear discrimination function on a two‐dimensional surface. If this kind of primary diagnosis of spinal deformities can be automated, group diagnosis in schools would be more efficient and useful. The authors use their method, perform discrimination tests on 120 normal and abnormal cases, and find a recognition rate of 87.9%. © 2001 Scripta Technica, Syst Comp Jpn, 32(7): 20–28, 2001
A musical structure model and its visual mechanism for hypertext score systems
Authors: Ariyoshi Yusuke , Shimojo Shinji , Miyahara Hideo
Published: August 2002

In order to perform with consistency a musical score having multiple parts, as in an orchestra or a chorus, it is important that the conductor and performers share its musical semantic structures. However, past studies of the expression or visualization of musical semantic structure in the field of music information processing have dealt with scores having a single voice part. In this paper, we propose a new electronic musical score system, “HyperScore,” based on the hypertext data model. Expanding the hypertext data model and its visualization mechanism, HyperScore has a flexible semantic structure model and a strong visualization mechanism which help the conductor and performers understand the semantics of the score and communicate with each other. The musical semantic structure model consists of three components: phrase–motif–note tree structures of the musical score, musical structures such as particular musical forms, and links among these structures. The visualization mechanism generates various views of the semantic structure of the music from different perspectives. The view is generated by a visualization mechanism specifying four parameters: the XY axes, display rules, selection, and granularity. The view illustrates the musical semantics of series of notes clearly by their position in the view and their display attributes. © 2001 Scripta Technica, Syst Comp Jpn, 32(7): 39–51, 2001
Distributed shared memory with log based consistency for operations with commutative law or associative law
Authors: Hirayama Hideaki , Honda Hiroki , Yuba Toshitsugu
Published: August 2002

With progress in high‐performance networks, cluster systems with high‐performance and inexpensive work stations or personal computers are attracting much attention. For the cluster systems to become popular, it is necessary that it be easy to develop programs on them. Distributed Shared Memory is the key to achieving this objective. But Distributed Shared Memory cannot achieve high performance for all application programs. In particular, programs which frequently modify the same fields by multiple nodes cannot attain high performance with Distributed Shared Memory. In this paper, we propose Distributed Shared Memory with Log Based Consistency for such application programs, such as aggregation applications in the business application area. In this scheme, consistency is maintained by transferring logs among multiple nodes for operations with the commutative law or associative law. Distributed Shared Memory with Log Based Consistency can achieve much better performance than the traditional Distributed Shared Memory. Its performance is almost the same as that of SMP parallel computers. © 2001 Scripta Technica, Syst Comp Jpn, 32(8): 10–19, 2001
On‐line testing in fuzzy controllers
Authors: Kamiura Naotake , Hata Yutaka
Published: August 2002

This paper proposes an on‐line testing procedure for fuzzy controllers. A stuck‐at‐0 fault and a stuck‐at‐1 fault in the membership function are assumed as the fault models. In the proposed method, up to 7 extra functions are considered for each input variable in the antecedent part. The antecedent part and the consequent part can be tested in parallel. In the testing of the antecedent part, the sum of function values (degrees) derived based on the matching between the current measured input and the functions is observed. In the testing of the consequent part, the sum of the area of the output fuzzy sets, the sum of the degrees of applicability, and the sum of 7 degrees in the output fuzzy sets are observed. These procedures make it possible to handle simultaneously a fault in the antecedent part and a fault in the consequent part. Through comparisons with other methods, the proposed method is shown to be useful in terms of the number of faults that can be handled and the ease of application to multi‐input controllers. © 2001 Scripta Technica, Syst Comp Jpn, 32(8): 63–71, 2001
Building a design support tool for superscalar processors and its case studies
Authors: Kimura Yasunori , Shimura Kouya , Nishimoto Haruko , Kawaba Motoyuki , Eguchi Takeshi
Published: August 2002

We will describe Paratool, a support tool to efficiently design superscalar processors, and its case studies. Paratool is a software tool that predicts performance of superscalar processors being designed, using execution traces on a sequential processor, and it runs on a sequential processor. It can measure almost all microarchitectures for superscalar processors. It can measure an ideal microarchitecture, whose resources are limitless. Furthermore, we will describe the result of case studies and report findings designers tend to overlook. This support tool is useful not only for architecture design, but also for tuning of compilers/application software and education in universities. © 2001 Scripta Technica, Syst Comp Jpn, 32(12): 67–79, 2001
Efficient verification by exploiting symmetry and abstraction
Authors: Toshima Hiroshi , Yoneda Tomohiro
Published: August 2002

In general, systems are comprised of a large number of elements and might be very symmetric. In verification of such systems, they are reduced while upkeeping their global structure and verified with the intuitive expectation that the verification of such reduced systems will yield almost the same results as those of the original ones. However, such verifications do not guarantee the success of original system verifications. In this paper, the target is verification of arbitrary scale systems with star‐shape configuration which can be expressed by Petri nets. The proposed algorithm explores the reachable state space with no dependency on system scale. © 2001 Scripta Technica, Syst Comp Jpn, 32(14): 41–53, 2001
Scanning force microscopy of two‐dimensional structure formation in thin humic acid films
Authors: Mertig Michael , Klemm Denis , Zänker Harald , Pompe Wolfgang
Published: August 2002

Humic acid films have been prepared by spin‐coating on mica substrates and imaged by scanning force microscopy (SFM). The deposited humic acid films exhibit typical dewetting patterns formed by rupture of the spin‐coated film. Two‐dimensional Fourier analysis of the SFM images shows that the observed film structures can be well described by a characteristic wavelength that depends on both the concentration of the humic acid solution and the evaporation rate of the solvent. The latter can be controlled by the relative humidity during film preparation. Thus, the investigations give clear evidence that structure formation in thin humic acid films is caused by dewetting during film deposition. Copyright © 2002 John Wiley & Sons, Ltd.
Summary of ISO/TC 201 Standard: III ISO 14707:2000—Surface chemical analysis—Glow discharge spectrometry—Glow discharge optical emission spectrometry—Introduction for use
Authors: Bengtson A.
Published: August 2002

This International Standard gives guidelines for the use of glow discharge optical emission spectrometry (GDOES) for bulk and depth profile analysis of rigid solids. The sample is sputter etched in a glow discharge device and the element‐characteristic optical emission recorded simultaneously. The standard specifies the type of equipment used and gives general guidelines for the operation of such equipment. Measuring techniques and procedures for verification of analytical results also are given. Copyright © 2002 John Wiley & Sons, Ltd.
Functional data analysis with application to periodically stimulated foetal heart rate data. II: Functional logistic regression
Authors: Ratcliffe Sarah J. , Heller Gillian Z. , Leader Leo R.
Published: August 2002

We present a basis solution for the modelling of a binary response with a functional covariate plus any number of scalar covariates. This can be thought of as singular longitudinal data analysis as there are more measurements on the functional covariate than subjects in the study. The maximum likelihood parameter estimates are found using a basis expansion and a modified Fisher scoring algorithm. This technique has been extended to model a functional covariate with a repeated stimulus. We used periodically stimulated foetal heart rate tracings to predict the probability of a high risk birth outcome. It was found that these tracings could predict 94.1 per cent of the high risk pregnancies and without the stimulus, the heart rates were no more predictive than chance. Copyright © 2002 John Wiley & Sons, Ltd.
Sensitivity analysis of longitudinal binary quality of life data with drop‐out: an example using the EORTC QLQ‐C30
Authors: Van Steen Kristel , Curran Desmond , Molenberghs Geert
Published: August 2002

Analysing quality of life data (QOL) may be complicated for several reasons. Quality of life data not only involves repeated measures but is also usually collected on ordered categorical responses. In addition, it is evident that not all patients provide the same number of assessments, due to attrition caused by death or other medical reasons. In the recent statistical literature, increasing attention is given to methods which can handle non‐continuous outcomes in the presence of missing data. The aim of this paper is to investigate the effect on statistical conclusions of applying different modelling techniques to QOL data generated from an EORTC phase III trial. Treatment effects and treatment differences are of major concern. First, a random‐effects model is fitted, relating a binary longitudinal response (derived from the physical functioning scale of the QLQ‐C30) to several covariates. In a second approach, marginal models are fitted, retaining the response variable and the mean structure used before. The fitted marginal models only differ with respect to the considered estimation procedure: generalized estimating equations (GEE); weighted generalized estimating equations (WGEE), and maximum likelihood (ML). Copyright © 2001 John Wiley & Sons, Ltd.
Properties of the summary receiver operating characteristic (SROC) curve for diagnostic test data
Authors: Walter S. D.
Published: August 2002

The summary receiver operating characteristic (SROC) curve has been recommended to represent the performance of a diagnostic test, based on data from a meta‐analysis. However, little is known about the basic properties of the SROC curve or its estimate. In this paper, the position of the SROC curve is characterized in terms of the overall diagnostic odds ratio and the magnitude of inter‐study heterogeneity in the odds ratio. The area under the curve (AUC) and an indexQ*are discussed as potentially useful summaries of the curve. It is shown that AUC is maximized when the study odds ratios are homogeneous, and that it is quite robust to heterogeneity. An upper bound is derived for AUC based on an exact analytic expression for the homogeneous situation, and a lower bound based on the limit caseQ*, defined by the point where sensitivity equals specificity:Q*is invariant to heterogeneity. The standard error of AUC is derived for homogeneous studies, and shown to be a reasonable approximation with heterogeneous studies. The expressions for AUC and its standard error are easily computed in the homogeneous case, and avoid the need for numerical integration in the more general case. SE(AUC) and SE(Q*) are found to be numerically close, with SE(Q*) being larger if the odds ratio is very large. The methods are illustrated using data for the Pap smear screening test for cervical cancer, and for three tests for the diagnosis of metastases in cervical cancer patients. Copyright © 2002 John Wiley & Sons, Ltd.