bluuebunny/crossref_metadata_2025 huggingface dataset:
SOME ORDER DUALITIES IN LOGIC, GAMES AND CHOICES
Authors: MONJARDET BERNARD
Published: May 2007

We first present the concept of duality appearing in order theory, i.e. the notions of dual isomorphism and of Galois connection. Then, we describe two fundamental dualities, the duality extension/intention associated with a binary relation between two sets, and the duality between implicational systems and closure systems. Finally, we present two "concrete" dualities occuring in social choice and in choice functions theories.
WEBER POLYHEDRON AND WEIGHTED SHAPLEY VALUES
Authors: VASIL'EV VALERI
Published: May 2007

In this paper, we consider the relationship between the Weber set and the Shapley set being the set of all weighted Shapley values of a TU-game. In particular, we propose a new proof for the fact that the Weber set always includes the Shapley set. It is shown that the inclusion mentioned follows directly from the representation theorem for the Weber set, established by Vasil'ev and van der Laan (2002), Siberian Adv. Math., V.12, N2, 97–125. Since the representation theorem applied is formulated in terms of the dividend sharing systems belonging to the so-called Weber polyhedron, we pay strong attention to some monotonicity properties of this polyhedron. Specifically, by making use of induction techniques, a new proof of the strong monotonicity of the Weber d-systems is obtained, and a simplified description of the Weber polyhedron is given.
SURFACE CHEMISTRY FOR PROTEIN MICROARRAYS
Authors: GUO ATHENA , ZHU XIAOYANG
Published: May 2007

Protein microarray or protein chip is an important tool in proteomics. However, duplicating the success of the DNA chip for the protein chip has been difficult. This account discusses a key issue in protein microarray development, i.e., surface chemistry. Ideally, the surface chemistry for protein microarray fabrication should satisfy the following criteria: the surface resists nonspecific adsorption; functional groups for the facile immobilization of protein molecules of interest are readily available; bonding between a protein molecule and a solid surface is balanced to provide sufficient stability but minimal disturbance on the delicate three-dimensional structure of the protein; linking chemistry allows the control of protein orientation; the local chemical environment favors the immobilized protein molecules to retain their native conformation; and finally, the specificity of linking chemistry is so high that no pre-purification of proteins is required. Strategies to achieve such an ideal situation are discussed, with successful examples from our laboratories illustrated. Finally, the need of surface technology for membrane protein microarray fabrication is addressed.
FUNCTIONALITY COMPARISONS OF SINGLE AND MULTI-WALLED NANOTUBES WITH GRAPHITIC FIBERS
Authors: NURMAWATI M. H. , LOW B. J. , SOW C. H. , VALIYAVEETTIL S.
Published: May 2007

The large surface area of inert carbon nanotubes (CNTs) and carbon fibers (CFs) renders insufficient interaction between the CNTs and CFs with the organic matrix. The filler–matrix interactions consequently become important to ensure sufficient wetting and filler dispersion in the matrix. The optimized functionalization method for both the CNTs and CFs will improve the viability of the entities for applications. In this report, we present a comparison between single-walled, multi-walled CNTs and pitch-based CFs in terms of their susceptibility to oxidation. The effects of functionalization reactions and extent of reaction are analyzed in terms of morphology, destruction of graphitization and hydrophobicity of the CNTs and CFs.
DE-NOISING AND BASELINE WANDERING REMOVAL OF ELECTROCARDIOGRAM USING DOUBLE DENSITY DISCRETE WAVELET
Authors: KUMARI R. SHANTHA SELVA , SADASIVAM V.
Published: May 2007

In this paper, an off-line double density discrete wavelet transform based de-noising and baseline wandering removal methods are proposed. Different levels decomposition is used depending upon the noise level, so as to give a better result. When the noise level is low, three levels decomposition is used. When the noise level is medium, four levels decomposition is used. When the noise level is high, five levels decomposition is used. Soft threshold technique is applied to each set of wavelet detail coefficients with different noise level. Donoho's estimator is used as a threshold for each set of wavelet detail coefficients. The results are compared with other classical filters and improvement of signal to noise ratio is discussed. Using the proposed method the output signal to noise ratio is 19.7628 dB for an input signal to noise ratio of -7.11 dB. This is much higher than other methods available in the literature. Baseline wandering removal is done by using double density discrete wavelet approximation coefficients of the whole signal. This is an unsupervised method allowing the process to be used in off-line automatic analysis of electrocardiogram. The results are more accurate than other methods with less effort.
FROM SEMANTICOBJECTS TO SEMANTIC SOFTWARE ENGINEERING
Authors: SHEU PHILLIP C.-Y. , KITAZAWA ATSUSHI
Published: May 2007

One of the most important pieces of a database management system is its query language and the underlying algebra. This paper describes the query language of SemanticObjects, a development framework for object relational applications, and its associated object relational algebra. The paper also describes a semantic software engineering methodology that streamlines the development of object relational applications based on SemanticObjects.
BIO-INSPIRED PROCESSING AND PROPAGATION OF SEMANTICS IN LOOSELY COUPLED COMPUTING ENVIRONMENTS
Authors: JACOB CARSTEN , LINNER DAVID , PFEFFER HEIKO , RADUSCH ILJA
Published: May 2007

Human-centric computing has grown to be the major influence in today's computing research. Due to demand from industry and even lawmakers for easy-to-use computer systems, the user is now regarded as being the center of a ubiquitously available environment that supports the execution of task and anticipates user actions. This environment allows for the establishment of completely new ways for the delivery of legacy services and represents an opportunity for the introduction of a new type of services, addressing the user-focused service consumption. As a cause of this shift, the increasing saturation of everyday environments with computing devices can be identified. This saturation implies a numerical growth of computing systems and entails an increasing complexity, which negatively influences maintainability and manageability. Moreover, the shortcomings caused by the mobility of system elements, a common trait of human-centric environments, require consideration about the reliability of cooperative actions. In this paper, we present an approach that copes with complexity and dynamic while making service-oriented systems autonomous by the use of bio-inspired concepts. In particular, the aim is to make service architectures environment-aware. Thus, service architectures are supposed to adapt autonomously to their current environment like biological species do to survive. This approach requires services to obtain knowledge about characteristics and state of the environment through gathering semantically enhanced information about the context of the computing environment, which is intended to help in forming a virtual counterpart of the real world as reference for service adaptation. For this purpose, we illustrate the architecture for context provisioning in highly dynamic computing environments. As base for this architecture a middleware is introduced utilizing a loosely coupled interaction model. Moreover, a pheromone-based concept is outlined to optimize the dissemination of context data in the absence of adequate context sources.
ANALYSIS OF COGNITIVE SOCIAL AND KNOWLEDGE NETWORKS FROM ELECTRONIC COMMUNICATION
Authors: PATHAK NISHITH , MANE SANDEEP , SRIVASTAVA JAIDEEP
Published: May 2007

This paper explains the classical social network analysis and discusses how computer networks effect a shift in constructing social networks. The paper then concentrates on analyzing cognitive aspects of a social network, explaining a simple but scalable approach for modeling a socio-cognitive network. Novel measures using such a socio-cognitive network model are defined and applications of such measures to extract useful information is illustrated on the Enron email dataset. The paper then describes a Dempster-Schafer theory based approach towards modeling a cognitive knowledge network and uses the Enron email dataset to illustrate how the proposed model can be used to capture actors' perceptions in a knowledge network. The paper concludes with a summary of the proposed models and a discussion on new research directions that can arise due to such cognitive analyses of electronic communication data.
Systematic Review: Do We Need a New Gastro-Oesophageal Reflux Disease Questionnaire?
Authors: Stanghellini V. , Armstrong D. , Mönnikes H. , Bardhan K.D.
Published: May 2007

Background: Gastro-oesophageal reflux disease (GERD) is highly prevalent in Western countries. Because the majority of patients do not present with endoscopic abnormalities, the assessment of the symptom severity and quality of life, and their response to treatment, has become increasingly important. Self-assessed symptom questionnaires are now key instruments in clinical trials. Aim: To evaluate the validity of available GERD measurement tools. Methods: An ideal GERD symptom assessment instrument, suitable as a primary end-point for clinical trials, should possess the following characteristics: (i) be sensitive in patients with GERD; (ii) cover the frequency and intensity of typical and atypical GERD symptoms; (iii) be multidimensional (cover all symptom dimensions); (iv) have proven psychometric properties (validity, reliability and responsiveness); (v) be practical and economical; (vi) be self-assessed; (vii) use ‘word pictures’ which are easy to understand for patients; (viii) respond rapidly to changes (responsiveness over short time intervals); (ix) be used daily to assess changes during and after therapy; and (x) be valid in different languages for international use. Results: A literature review revealed five scales that met some of the above characteristics, but did not fulfil all criteria. Conclusion: There is a need for a new evaluative tool for the assessment of GERD symptoms and their response to therapy.
Evaluation of GERD Symptoms during Therapy
Authors: Bardhan K.D. , Stanghellini V. , Armstrong D. , Berghöfer P. , Gatz G. , Mönnikes H.
Published: May 2007

Background/Aims: The changes in gastroesophageal reflux disease (GERD)-related symptoms on treatment are variously described, but currently available questionnaires have shortcomings. We therefore developed a self-assessment reflux questionnaire (ReQuest™). This article describes the process of development and testing. Materials and Methods: For the first version of ReQuest™the symptom spectrum of GERD and the various symptom descriptions were investigated. The 67 identified symptom descriptions were condensed empirically into 6 dimensions, to which a 7th dimension on general well-being was added. The symptom burden of the dimensions was measured by frequency and/or intensity. ReQuest™ was translated into different languages and then tested in focus groups. The initial validation was based on data from a clinical trial of patients with erosive GERD, treated with pantoprazole 20 or 40 mg daily for 28 days. Factor analyses determined the contribution of each symptom to the different dimensions. Additionally, correlation analyses between the identified factors and the dimensions were performed. Results: On the basis of factor analyses, ReQuest™ was reduced to a 60-item scale. The factors generated correlated strongly with the dimensions and confirmed the empirical process mathematically. Conclusion:ReQuest™ provides a valuable, self-assessment tool for evaluating the daily treatment response in patients with erosive GERD.
Novel Measurement of Rapid Treatment Success with ReQuestTM: First and Sustained Symptom Relief as Outcome Parameters in Patients with Endoscopy-Negative GERD Receiving 20 mg Pantoprazole or 20 mg Esomeprazole
Authors: Mönnikes Hubert , Pfaffenberger Bernd , Gatz Gudrun , Hein Jasper , Bardhan Karna Dev
Published: May 2007

Background/Aims: A prime concern for gastroesophageal reflux disease (GERD) patients is fast symptom control. Sparse valid information is available on the rapidity of the effect of proton pump inhibitors in providing symptom relief. The new reflux questionnaire ReQuestTM is validated for daily assessment of changes in GERD symptoms. Therefore, this study investigated the efficacy of 20 mg pantoprazole and 20 mg esomeprazole with regard to the time to symptom relief in patients with endoscopy-negative GERD (enGERD) using ReQuestTM. Methods: 529 patients were treated with pantoprazole or esomeprazole over 4 weeks. ReQuestTM symptom scores were assessed daily. The mean and median times to first and sustained symptom relief were determined. Results: Median time to first symptom relief was 2 days for both drugs (intention-to-treat population). The median time to sustained symptom relief was 3 days shorter with pantoprazole (10.0 vs. 13.0 days). The Hodges-Lehmann estimator for the difference in time to reach first and sustained symptom relief between both groups was 0.00 days. For both variables the one-sided 95% CI (Moses) was [0.00; ∞[, documenting no significant differences between the treatment groups. Conclusions: The rapidity of symptom control can be evaluated by clinically significant parameters using ReQuestTM. Pantoprazole and esomeprazole are equally effective in the time to first and sustained symptom relief.
Pantoprazole 40 mg Is as Effective as Esomeprazole 40 mg to Relieve Symptoms of Gastroesophageal Reflux Disease after 4 Weeks of Treatment and Superior regarding the Prevention of Symptomatic Relapse
Authors: Glatzel Dirk , Abdel-Qader Muwafeg , Gatz Gudrun , Pfaffenberger Bernd
Published: May 2007

Background/Aim: Little is known about the symptom course during and after treatment of gastroesophageal reflux disease (GERD). Here we address this question in patients with erosive GERD treated with pantoprazole or esomeprazole 40 mg once daily using the validated reflux questionnaire ReQuestTM. Methods: Of 585 patients enrolled, 561 (intention-to-treat; ITT) patients with endoscopically confirmed GERD grades A–D (Los Angeles Classification) were randomized. To assess the GERD symptomatology, the patients completed the ReQuest daily, and analysis was done prior to (7 days), during (28 days), and after treatment (7 days). The mean scores (last 3 treatment days) of the subscale ReQuestTM-GI (gastrointestinal complaints) were compared between both groups. After the end of treatment, the number of symptom episodes and the rate of relapses were calculated. Results: Noninferiority of pantoprazole versus esomeprazole during treatment was shown (mean ReQuest-GI score). During the posttreatment period, the proportion of patients experiencing a symptomatic relapse (51 vs. 61%, p = 0.0216, ITT) and the number of symptom episodes (0.56 vs. 0.74, p = 0.0095, ITT) were significantly lower on pantoprazole than on esomeprazole. Conclusions: Pantoprazole 40 mg was at least as effective as esomeprazole 40 mg for relieving GERD symptoms. During the posttreatment phase, patients on pantoprazole had a significantly lower risk to relapse and experienced significantly fewer symptom episodes.
Physicochemical Characterization of El Tor Vibriophage S20
Authors: Dutta Moumita , Ghosh Amar N.
Published: May 2007

Objective:To characterize Vibrio cholerae El Tor typing phage S20 (ATCC No. 51352-B3). Methods and Results: The phage has a hexagonal head and a short tail. Cryo-electron microscopy and three-dimensional image reconstruction showed that the phage head has icosahedral symmetry. The phage has two major structural polypeptides of 50 and 42 kDa. Adsorption of the phage to its host followed a biphasic kinetics and its intracellular growth is characterized by a latent period of 12 min and a burst size of around 60 particles per infected cell. The phage was found to be stable at a pH range 5.0–9.0 and moderately thermotolerant and highly UV sensitive. Phage genome comprises a 40.7 ± 1.5-kb linear DNA molecule with random circular permutation and terminal redundancy. The restriction endonucleases AccI, HpaII, HaeIII, HindIII, EcoRV, HincII, DraI and XmnI cut vibriophage S20 DNA. Conclusion: Vibriophage S20, which belongs to Podoviridae, has an icosahedral head and the genome, which is double-stranded linear DNA, has random circular permutation and terminal redundancy.
A Patient-specific in vivo Tumor and Normal Tissue Model for Prediction of the Response to Radiotherapy
Authors: Antipas V. P. , Uzunoglu N. K. , Stamatakos G. S.
Published: May 2007

Objectives:
Integration of multiscale experimental cancer biology through the development of computer simulation models seems to be a necessary step towards the better understanding of cancer and patient-individualized treatment optimization. The integration of a four-dimensional patient-specific model of in vivo tumor response to radiotherapy developed by our group with a model of slowly responding normal tissue based on W. Duechting’s approach is presented in this paper. The case of glioblastoma multiforme and its surrounding neural tissue is addressed as a modeling paradigm.

Methods:
A cubic discretizing mesh is superimposed upon the anatomic region of interest as is reconstructed from pertinent imaging (e.g. MRI) data. On each geometrical cell of the mesh the most crucial biological “laws” e.g. metabolism, cell cycling, tumor geometry changes, cell kill following irradiation etc. are applied. Slowly responding normal neural tissue is modeled by a functional compartment containing indivisible cells and a divisible compartment containing glial cells.

Results:
The model code has been executed for a simulated period normally covering the radiotherapy course duration and extending a few days after its completion. The following schemes have been simulated: standard fractionation, hyperfractionation, accelerated fractionation, accelerated hyperfractionation and hypofractionation. The predictions are in agreement with the outcome of the RTOG 83-02 phase I/II trial, the retrospective study conducted by Sugawara et al. and the theoretical predictions of Duechting et al.

Conclusions:
The presented model, although oversimplified, may serve as a basis for a refined simulation of the biological mechanisms involved in tumor and normal tissue response to radiotherapy.
Respiratory-phase Domain Analysis of Heart Rate Variability Can Accurately Estimate Cardiac Vagal Activity during a Mental Arithmetic Task
Authors: Tachibana M. , Takamasu K. , Kotani K.
Published: May 2007

Objectives:
The objectives of this paper were to present a method to extract the amplitude of RSA in the respiratory-phase domain, to compare that with subjective or objective indices of the MWL (mental workload), and to compare that with a conventional frequencyanalysis in terms of its accuracy during a mental arithmetic task.

Methods:
HRV (heart rate variability), ILV (instantaneous lung volume), and motion of the throat were measured under a mental arithmetic experiment and subjective and objective indices were also obtained. The amplitude of RSA was extracted in the respiratory-phase domain, and its correlation with the load level was compared with the results of the frequencydomain analysis, which is the standard analysis of the HRV.

Results:
The subjective and objective indices decreased as the load level increased, showing that the experimental protocol was appropriate. Then, the amplitude of RSA in the respiratory-phase domain also decreased with the increase in the load level. The results of the correlation analysis showed that the respiratory-phase domain analysis has higher negative correlations, −0.84 and −0.82, with the load level as determined bysimplecorrelation and rankcorrelation, respectively, than does frequencyanalysis, for which the correlations were found to be −0.54 and −0.63, respectively. In addition, it was demonstrated thatthe proposed method could be applied to the short-term extraction of RSA amplitude.

Conclusions:
We proposed a simple and effective method to extract the amplitude of the respiratory sinus arrhythmia (RSA) in the respiratory-phase domain and the results show that this method can estimate cardiac vagal activity more accurately than frequency analysis.
Modeling Length of Stay as an Optimized Two-class Prediction Problem
Authors: Peek N. , Voorbraak F. , Jonge E. de , Mol B. A. J. M. de , Verduijn M.
Published: May 2007

Objectives:
To develop a predictive model for the outcome length of stay at the Intensive Care Unit (ICU LOS), including the choice of an optimal dichotomization threshold for this outcome. Reduction of prediction problems of this type of outcome to a two-class problem is a common strategy to identify high-risk patients.

Methods:
Threshold selection and model development are performed simultaneously. From the range of possible threshold values, the value is chosen for which the corresponding predictive model has maximal precision based on the data. To compare the precision of models for different dichotomizations of the outcome, the MALOR performance statistic is introduced. This statistic is insensitive to the prevalence of positive cases in a two-class prediction problem.

Results:
The procedure is applied to data from cardiac surgery patients to dichotomize the outcome ICU LOS. The class probabilitytree method is used to develop predictive models. Within our data, the best model precision is found at the threshold of seven days.

Conclusions:
The presented method extends existing procedures for predictive modeling with optimization of the outcome definition for predictive purposes. The method can be applied to all prediction problems where the outcome variable needs to be dichotomized, and is insensitive to changes in the prevalence of positive cases with different dichotomization thresholds.
Optimizing the Interventional Cardiology Facility: Services Integration in Routine Workflow
Authors: Kalogeropoulos A. , Alexopoulos D. , Nikiforidis G. , Gortzis L.
Published: May 2007

Objectives:
Integration of administrative and clinical data, imaging, and expert services, although challenging, is a key requirement in contemporary interventional cardiology facilities (ICF). We propose a workflow-oriented hybrid system to support the ICF and investigate its feasibility and effectiveness in a referral medical center.

Methods:
We have developed a Java-powered hybrid system (NetCARDIO), able to support over web synchronous and asynchronous data management, realtime multimedia data telemonitoring and continuous telementoring. Data regarding procedural rates, treatment planning and radiation exposure were collected over a two-year period of routine NetCARDIO implementation (July 2002 to June 2004) and compared with data from an immediately preceding period of equal duration (January 2000 to December 2001).

Results:
During the NetCARDIO period, 163 ±11 coronary procedures per month were performed vs. 77 ±15 during the control period (p <0.001). Percutaneous coronary intervention was delivered ‘ad hoc’ in 88% of eligible patients vs. 45% (p <0.001). Mean fluoroscopy time per coronary lesion treated decreased from 594 ± 82sto 540 ±94s (p < 0.001). Annual radiation exposure of expert interventionistswas decreased by 22%. Electronic storage significantly reduced archiving costs.

Conclusions:
Real-time multimodal services sharing combined with powerful database capabilities is feasible through a web-based structure, significantly enhancing performance and cost-effectiveness of ICF. Further research is needed to promote integration of additional data sources and services.
Systematic Analysis of Signaling Pathways Using an Integrative Environment
Authors: Breit M. , Pfeifer B. , Baumgartner C. , Modre-Osprian R. , Tilg B. , Visvanathan M.
Published: May 2007

Introduction:
Understanding the biological processes of signaling pathways as a whole system requires an integrative software environment that has comprehensive capabilities. The environment should include tools for pathway design, visualization, simulation and a knowledge base concerning signaling pathways as one. In this paper we introduce a new integrative environment for the systematic analysis of signaling pathways.

Methods:
This system includes environments for pathway design, visualization, simulation and a knowledge base that combines biological and modeling information concerning signaling pathways that provides the basic understanding of the biological system, its structure and functioning. The system is designed with a client-server architecture. It contains a pathway designing environment and a simulation environment as upper layers with a relational knowledge base as the underlying layer.

Results:
The TNFα-mediated NF-κB signal transduction pathway model was designed and tested using our integrative framework. It was also useful to define the structure of the knowledge base. Sensitivity analysis of this specific pathway was performed providing simulation data. Then the model was extended showing promising initial results.

Conclusion:
The proposed system offers a holistic view of pathways containing biological and modeling data. It will help us to perform biological interpretation of the simulation results and thus contribute to a better understanding of the biological system for drug identification.
Towards Semantic Interoperability for Electronic Health Records
Authors: Knaup P. , Hovenga E. J. S. , Heard S. , Garde S.
Published: May 2007

Objectives:
In the field of open electronic health records (EHRs), openEHR as an archetype-based approach is being increasingly recognised. It is the objective of this paper to shortly describe this approach, and to analyse how openEHR archetypes impact on health professionals and semantic interoperability.

Methods:
Analysis of current approaches to EHR systems, terminology and standards developments. In addition to literature reviews, we organised face-to-face and additional telephone interviews and tele-conferences with members of relevant organisations and committees.

Results:
The openEHR archetypes approach enables syntactic interoperability and semantic interpretability – both important prerequisites for semantic interoperability. Archetypes enable the formal definition of clinical content by clinicians. To enable comprehensive semantic interoperability, the development and maintenance of archetypes needs to be coordinated internationally and across health professions. Domain knowledge governance comprises a set of processes that enable the creation, development, organisation, sharing, dissemination, use and continuous maintenance of archetypes. It needs to be supported by information technology.

Conclusions:
To enable EHRs, semantic interoperability is essential. The openEHR archetypes approach enables syntactic interoperability and semantic interpretability. However, without coordinated archetype development and maintenance, ‘rank growth’ of archetypes would jeopardize semantic interoperability. We therefore believe that openEHR archetypes and domain knowledge governance together create the knowledge environment required to adopt EHRs.
Advances in Medical Image Computing
Authors: Horsch A. , Meinzer H.-P. , Handels H.
Published: May 2007

Objectives:
Medical image computing has become a key technology in high-tech applicationsin medicine. Nowadays, medical image computing techniques are applied in daily routine in various medical disciplines. However, further developments are needed to improve computer-aided diagnoses and computer-assisted therapy planning and performance in the future. In this issue selected contributions of the German Conference on Medical Image Processing (BVM) are assembled to present latest advances in the field of medical image computing.

Methods:
The winners of scientific awards of the German Conferences on Medical Image Processing (BVM) 2005 and 2006 were invited to submit a manuscript on their latest developments and results for possible publication in Methods of Information in Medicine. Finally, eleven excellent papers were selected to describe important aspects of recent advances in the field of medical image computing.

Results:
The selected papers give an impression of the broad range and heterogeneity of new developments in the field of medical image computing. New methods for improved image reconstruction, image segmentation, modelling of organs, as well as methodical improvements of non-linear image registration algorithms are presented together with applications of image analysis methods in different medical disciplines.

Conclusions:
The selected articles describe different aspects of the intense development in medical image computing. The image computing methods presented enable new insights into the patient’s image data and have the future potential to improve medical diagnostics and patient treatment.
Intensity Gradient Based Registration and Fusion of Multi-modal Images
Authors: Modersitzki J. , Haber E.
Published: May 2007

Objectives:
A particular problem in image registration arises for multi-modal images taken from different imaging devices and/or modalities. Starting in 1995, mutual information has shown to be a very successful distance measure for multi-modal image registration. Therefore, mutual information is considered to be the state-of-the-art approach to multi-modal image registration. However, mutual information has also a number of well-known drawbacks. Its main disadvantage is that it is known to be highly non-convexand hastypicallymanylocal maxima.

Methods:
This observation motivates us to seek a different image similarity measure which is better suited for optimization but as well capable to handle multimodal images.

Results:
In this work, we investigate an alternative distance measure which is based on normalized gradients.

Conclusions:
As we show, the alternative approach is deterministic, much simpler, easier to interpret, fast and straightforward to implement, faster to compute, and also much more suitable to numerical optimization.
Structure-preserving Interpolation of Temporal and Spatial Image Sequences Using an Optical Flow-based Method
Authors: Säring D. , Handels H. , Ehrhardt J.
Published: May 2007

Objectives:
Modern tomographic imaging devices enable the acquisition of spatial and temporal image sequences. But, the spatial and temporal resolution of such devices is limited and therefore image interpolation techniques are needed to represent images at a desired level of discretization. This paper presents a method for structure-preserving interpolation between neighboring slices in temporal or spatial image sequences.

Methods:
In a first step, the spatiotemporal velocity field between image slices is determined using an optical flow-based registration method in order to establish spatial correspondence between adjacent slices. An iterative algorithm is applied using the spatial and temporal image derivatives and a spatiotemporal smoothing step. Afterwards, the calculated velocity field is used to generate an interpolated image at the desired time by averaging intensities between corresponding points. Three quantitative measures are defined to evaluate the performance of the interpolation method.

Results:
The behaviorand capability of the algorithm is demonstrated by synthetic images. A population of 17 temporal and spatial image sequences are utilized to compare the optical flow-based interpolation method to linear and shape-based interpolation. The quantitative results show that the optical flow-based method outperforms the linear and shape-based interpolation statistically significantly.

Conclusions:
The interpolation method presented is able to generate image sequences with appropriate spatial or temporal resolution needed for image comparison, analysis or visualization tasks. Quantitative and qualitative measures extracted from synthetic phantoms and medical image data show that the new method definitely has advantages over linear and shape-based interpolation.
Ultrasound Cerebral Perfusion Analysis Based on a Mathematical Model for Diminution Harmonic Imaging
Authors: Meyer-Wiethe K. , Seidel G. , Aach T. , Kier C.
Published: May 2007

Objectives:
Cerebral vascular diseases are detectable by CT/MRI-based methods. Drawbacks of these methods are that they are expensive, time-consuming and intolerable to critically ill patients. Ultrasound, as an inexpensive bedside method, promises to become an alternative. Among other harmonic imaging methods, the diminution harmonic imaging (DHI) method is known, which determines perfusion-related parameters by analyzing ultrasound contrast agent (UCA) diminution kinetics based on constant UCA infusion. The shortcoming of DHI is that the used mathematical model can only determine these parameters by least squares fitting the model onto the data.

Methods:
In this work, the underlying mathematical model is further developed such that it becomes possible to directly calculate the parameters from the image data. Furthermore, the new model offers an improved way to estimate the spatial distribution of the destruction coefficient necessary for accurately determining the destruction power of the ultrasound pulse on the contrast agent.

Results:
The direct calculation of the perfusion coefficient is much faster thanthe former fitting of the model. Perfusion as well as destruction coefficients are displayed as color-coded images. In an example, a region with perfusion deficits (as shown in a MR image of the same patient) is clearly identifiable.

Conclusions:
Displaying the parameters as color-coded images facilitates result interpretation for the diagnosing physician. The results are preliminary and still have to be validated, but they suggest that the new DHI model improves the significance of ultrasound as a diagnostic help.
Towards Fully Automatic Acquisition of Multimodal Cytopathological Microscopy Images with Autofocus and Scene Matching
Authors: Würflinger T. , Ropers S.-O. , Böcking A. , Aach T. , Bell A. A.
Published: May 2007

Objectives:
To increase the chance for a cure, cancer must be detected as early as possible. This can be achieved with cytopathological diagnostic methods. For a further increase of the diagnostic accuracy of these methods we introduced the multimodal cell analysis, viz, cells on the slide have to be relocalized to enable successive analysis of identical cells in different stains. For practical reasons the relocalization step must be automated.

Methods:
For a fully automatic acquisition of successive cell images we use a passive autofocus that is adaptive to the material, i.e., to the cells, followed by a comparison of the scenes, i.e., the cell constellation, of two such obtained images from different stains. In case that no sub-scene match can be found the search is extended to the surrounding area. A set of 1 556 scenes from seven specimens have been subject to our algorithm. The automatically relocalized and acquired images from a second stain have been manually compared to the images from a first stain.

Results:
An overall relocalization rate of 85.4% is achieved. 14.3% of the images could not be relocalized and are lost for the following diagnostic process, while the critical case of erroneously matched images was observed in only 0.3% of cases.

Conclusions:
We could show that it is possible to automatically acquire images of successive stains of identical cells on cytopathological specimens. The method presented achieves acceptable relocalization rates. Wrong image acquisitions are very rare and can mostly be ascribed to images with single cells, i.e., without scene information.
Computer-assisted Diagnosis for Early Stage Pleural Mesothelioma
Authors: Jäger P. , Vogel S. , Knepper A. , Kraus T. , Aach T. , Chaisaowong K.
Published: May 2007

Objectives:
Pleural thickenings as biomarker of exposure to asbestos may evolve into malignant pleural mesothelioma. Foritsearly stage, pleurectomy with perioperative treatment can reduce morbidity and mortality. The diagnosis is based on a visual investigation of CT images, which is a time-consuming and subjective procedure. Our aim is to develop an automatic image processing approach to detect and quantitatively assess pleural thickenings.

Methods:
We first segment the lung areas, and identify the pleural contours. A convexity model is then used together with a Hounsfield unit threshold to detect pleural thickenings. The assessment of the detected pleural thickenings is based on a spline-based model of the healthy pleura.

Results:
Tests were carried out on 14 data sets from three patients. In all cases, pleural contours were reliably identified, and pleural thickenings detected. PC-based Computation times were 85 min for a data set of 716 slices, 35 min for 401 slices, and 4 min for 75 slices, resulting in an average computation time of about 5.2 s per slice. Visualizations of pleurae and detected thickeningswere provided.

Conclusion:
Results obtained so far indicate that our approach is able to assist physicians in the tedious task of finding and quantifying pleural thickenings in CT data. In the next step, our system will undergo an evaluation in a clinical test setting using routine CT data to quantifyits performance.
Concurrent Recording and Regeneration of Visual and Olfactory Information Using Odor Sensor
Authors: Yamanaka Takao , Nimsuk Nitikarn , Nakamoto Takamichi
Published: May 2007

In this paper, a method of concurrent recording and regeneration of visual and olfactory information is presented using electronic nose technology. To accomplish this objective, the sensor response patterns of odors in the atmosphere were measured using QCM (quartz crystal microbalance) odor sensors with partially overlapping specificities. Then the odors were identified from the response patterns using LVQ (learning vector quantization), a pattern classification algorithm of neural networks with supervised learning. Visual information, presented as a movie, was captured using a digital video camera; concurrently, odors using odor sensor responses were paired to the video. The recorded visual and olfactory information was evaluated by sensory tests to investigate the effectiveness of the proposed system. As a result, it was found that the olfactory information recorded using the proposed method was appropriate for odor regeneration associated with the movie.
Design and Evaluation of a Real-World Virtual Environment for Architecture and Urban Planning
Authors: Drettakis George , Roussou Maria , Reche Alex , Tsingos Nicolas
Published: May 2007

In this paper we present a user-centered design approach to the development of a Virtual Environment (VE), by utilizing an iterative, user-informed process throughout the entire design and development cycle. A preliminary survey was first undertaken with end users, that is, architects, chief engineers, and decision makers of a real-world architectural and urban planning project, followed by a study of the traditional workflow employed. We then determined the elements required to make the VE useful in the real-world setting, choosing appropriate graphical and auditory techniques to develop audiovisual VEs with a high level of realism. Our user-centered design approach guided the development of an appropriate interface and an evaluation methodology to test the overall usability of the system. The VE was evaluated both in the laboratory and, most importantly, in the users' natural work environments. In this study we present the choices we made as part of the design and evaluation methodologies employed, which successfully combined research goals with those of a real-world project.

Among other results, this evaluation suggests that involving users and designers from the beginning improves the effectiveness of the VE in the context of the real world urban planning project. Furthermore, it demonstrates that appropriate levels of realism, in particular spatialized 3D sound, high-detail vegetation, and shadows, as well as the presence of rendered crowds, are significant for the design process and for communicating about designs; they enable better appreciation of overall ambience of the VE, perception of space and physical objects, as well as the sense of scale. We believe this study is of interest to VE researchers, designers, and practitioners, as well as professionals interested in using VR in their workplace.
Radar and Rain Gauge Analysis of the Extreme Rainfall during Hurricane Danny’s (1997) Landfall
Authors: Medlin Jeffrey M. , Kimball Sytske K. , Blackwell Keith G.
Published: May 2007

As a minimal hurricane, Danny moved over Mobile Bay around 0900 UTC 19 July 1997 and became stationary by midmorning, while situated within a synoptic col. Danny then evolved into an asymmetric storm with an intensely convective rainband that produced torrential rainfall through 1200 UTC 20 July 1997. Danny’s center remained <100 km from the National Weather Service (NWS) Weather Surveillance Radar-1988 Doppler (WSR-88D) in Mobile, Alabama, for over 48 h, allowing long-term surveillance of the storm’s inner core. This event marked the first time the tropical Z–R relationship was employed on an operational WSR-88D system during tropical cyclone landfall. A radar-estimated maximum rainfall accumulation of 1097 mm (43.2 in.) was analyzed over southwestern Mobile Bay. A NWS cooperative rain gauge located on Dauphin Island, Alabama, measured 896 mm (35.28 in.). An adjacent standard rain gauge measured the highest rainfall amount of 932 mm (36.71 in.). This paper investigates the spatial and temporal distribution and potential magnitude of Danny’s torrential rainfall episode over coastal Alabama. It is shown that both gauges and radar seriously underestimated event rainfall. An estimate is given for what could have been the true event rainfall amount. In the case of the radar, the WSR-88D Algorithm Testing and Display System is used to obtain a better estimate of rainfall using higher dBZ caps than the operational 50 dBZ. In the case of the tipping-bucket rain gauge, wind and mechanical error estimates were applied in order to quantify rainfall underestimation.
The Boreal Summer Intraseasonal Oscillation Simulated in the NCEP Climate Forecast System: The Effect of Sea Surface Temperature
Authors: Seo Kyong-Hwan , Schemm Jae-Kyung E. , Wang Wanqiu , Kumar Arun
Published: May 2007

Observational evidence has indicated the important role of the interaction of the atmosphere with the sea surface in the development and maintenance of the tropical intraseasonal oscillation (ISO). However, improvements in ISO simulations with fully coupled atmosphere–ocean general circulation models are limited and model dependent. This study further examines the effect of air–sea coupling and the basic-state sea surface temperature (SST) associated with the boreal summer intraseasonal oscillation (BSISO) in a 21-yr free run with the recently developed NCEP coupled Climate Forecast System (CFS) model. For this, the CFS run is compared with an Atmospheric Model Intercomparison Project–type long-term simulation forced by prescribed SST in the NCEP Global Forecast System (GFS) model and flux-corrected version of CFS (referred to as CFSA). The GFS run simulates significantly unorganized BSISO convection anomalies, which exhibit an erroneous standing oscillation. The CFS run with interactive air–sea coupling has limited improvements, including the generation of intraseasonal SST variation preceding the convection anomaly by ∼10 days. However, this simulation still does not show the observed continuous northward propagation over the Indian Ocean due to a cold model bias. The CFSA run removes the cold bias in the Indian Ocean and the simulation of the development and propagation of BSISO anomalies are significantly improved. Enhanced and suppressed convection anomalies exhibit the observed quadrupole-like configuration, and phase relationships between precipitation and surface dynamic and thermodynamic variables for the northward propagation are shown to be coherent and consistent with the observations. It is shown that the surface meridional moisture convergence is an important factor for the northward propagation of the BSISO. On the other hand, both the GFS and CFS runs do not realistically simulate an eastward-propagating equatorial mode. The CFSA run produces a more realistic eastward-propagation mode only over the Indian Ocean and Java Sea due to the improved mean state in SST, low-level winds, and vertical wind shear. Reasons for the failure of farther eastward propagation into the west Pacific in CFSA are discussed. This study reconfirms the significance of air–sea interactions. More importantly, however, the results suggest that in order for the influence of the coupled air–sea interaction to be properly communicated, the mean state SST in the coupled model should be reasonably simulated. This is because the basic-state SST itself acts to sustain BSISO convection and it makes the large-scale dynamical environment (i.e., easterly vertical wind shear or low-level westerly zonal wind) more favorable for the propagation of the moist Rossby–Kelvin wave packet.
Reexamination of the Near-Surface Airflow over the Antarctic Continent and Implications on Atmospheric Circulations at High Southern Latitudes*
Authors: Parish Thomas R. , Bromwich David H.
Published: May 2007

Previous work has shown that winds in the lower atmosphere over the Antarctic continent are among the most persistent on earth with directions coupled to the underlying ice topography. In 1987, Parish and Bromwich used a diagnostic model to depict details of the Antarctic near-surface airflow. A radially outward drainage pattern off the highest elevations of the ice sheets was displayed with wind speeds that generally increase from the high interior to the coast. These winds are often referred to as “katabatic,” with the implication that they are driven by radiational cooling of near-surface air over the sloping ice terrain. It has been shown that the Antarctic orography constrains the low-level wind regime through other forcing mechanisms as well. Dynamics of the lower atmosphere have been investigated increasingly by the use of numerical models since the observational network over the Antarctic remains quite sparse. Real-time numerical weather prediction for the U.S. Antarctic Program has been ongoing since the 2000–01 austral summer season via the Antarctic Mesoscale Prediction System (AMPS). AMPS output, which is based on a polar optimized version of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model, is used for a 1-yr period from June 2003 to May 2004 to investigate the mean annual and seasonal airflow patterns over the Antarctic continent to compare with previous streamline depictions. Divergent outflow from atop the continental interior implies that subsidence must exist over the continent and a direct thermal circulation over the high southern latitudes results. Estimates of the north–south mass fluxes are obtained from the mean airflow patterns to infer the influence of the elevated ice sheets on the mean meridional circulation over Antarctica.