PC-based Workstation Research Articles

ПРОБЛЕМНІ ПИТАННЯ СТВОРЕННЯ ТА ВПРОВАДЖЕННЯ АВТОМАТИЗОВАНОГО НАВЧАЛЬНОГО КОМАНДНОГО ПУНКТУ У НАВЧАЛЬНИЙ ПРОЦЕС ВИЩОГО ВІЙСЬКОВОГО НАВЧАЛЬНОГО ЗАКЛАДУ

The most important reserve for increasing the effectiveness of the military management activities of the commander and headquarters of the unit in the preparation of combined arms combat is to provide the command and control body with more complete, reliable and operational information about the situation and conditions of hostilities and, on this basis, conduct high-quality and quick analysis to form a plan of action, get ahead of the enemy and achieving surprise. A promising way to improve the process of military decision-making by command and control units is the introduction of a decision support system. The decision support system is the central component of the automated command and control system that adequately reflects the real conditions, means of armed struggle and takes into account the laws of their functioning and mutual relations between them. The article deals with the issues of creating and introducing into the educational process an automated training command post for command and control of troops and subunits. On the basis of the simulation class of the academy, a project of an automated TCP control unit (subdivision) was developed, which makes it possible to automatically reproduce the process of making a military decision by G/S-structural units of the headquarters of a military formation according to NATO standards in an automated mode using a PC-based workstation. It is proposed to build a local network using a mixed type topology: "ring" and "passive star". Such a network structure simplifies the procedure for increasing the number of workstations and facilitates the maintenance and operation of the TCP. The composition of the tactical control unit includes a server, workstations of officers of the structural divisions of the headquarters, multi-channel communication consoles and an interactive whiteboard. The minimum requirements for the proposed network architecture are substantiated. It is shown that a geographic information system is a necessary component of the automated workplace, which implements a full set of functions for working with geodata necessary for a military command and control body. This was done on the basis of the Arc View GIS software package version 3.3. The list of capabilities of the proposed hardware-software complex of the TCP allows us to assert that this complex meets the requirements of at least a class C2 automated control system. The benefits of the implementation of the TCP are in the growth of the volume of information that the staff officers analyze, the high quality and reliability of the data, the comprehensive validity of the conclusions and proposals made, the reduction in the time spent on assessing the situation and making informed rational decisions throughout all seven stages of the standardized MDMP process.

DESARROLLO Y PUESTA EN MARCHA DE SOFTWARE DE TRACTOGRAFIA

Abstract: Diffusion weighted MRI can measure the random motion of water molecules in biological tissue. These motions are captured using magnetic gradients that dephase the precession of water molecules that move along the direction of the gradient. Dephasings show up as small attenuations in signal intensity.This information can be used in tissues such as muscles, spine, medulla and white matter to measure the ani-sotropy and assess fiber integrity. In this work, a new software for the post-processing of diffusion weighted MRI is presented.The software can read datasets from a variety of scanners. Diffusion is modeled using ellipsoids that are represented mathematically by means of a tensor, estimated from entry dataset. Various indices such as diffusion tensor eigenvalues, fractional anisotropy, types of anisotropy, mean diffu-sivity, and principal directions are computed. Results are interactively visualized by using axial planes or a three-dimensional approach. The software includes a nerve fiber tracing module. This tool works on PC-based workstations through a graphical user interface or by using the command line.

Flexible ex vivo phantoms for validation of diffusion tensor tractography on a clinical scanner

The aim of this study was to develop ex vivo diffusion tensor (DT) flexible phantoms. Materials were bundles of textile threads of cotton, monofilament nylon, rayon, and polyester bunched with spiral wrapping bands and immersed in water. DT images were acquired on a 1.5-Tesla clinical magnetic resonance scanner using echo planar imaging sequences with 15 motion probing gradient directions. DT tractography with seeding and a line-tracking method was carried out by software originally developed on a PC-based workstation. We observed relatively high fractional anisotropy on the polyester phantom and were able to reconstruct tractography. Straight tracts along the bundle were displayed when it was arranged linearly. It was easy to bend arcuately or bifurcate at one end; and tracts followed the course of the bundle, whether it was curved or branched and had good agreement with direct visual observation. Tractography with the other fibers was unsuccessful. The polyester phantom revealed a diffusion anisotropic structure according to its shape and would be utilizable repeatedly under the same conditions, differently from living central neuronal system. It would be useful to validate DT sequences and to optimize an algorithm or parameters of DT tractography software. Additionally, the flexibility of the phantom would enable us to model human axonal projections.

This Month in Gastroenterology

This Month in Gastroenterology

Introduction to Paper by Yongmin Kim, Ph.D., et al, ?Development of a PC-based Radiological Imaging Workstation?

THIS PAPER describes the University of Washington Graphics Systems Processor #1 (UWGSP1) that we developed in 1986 and 1987 as part of the DIN/PACS project at the University of Washington, which was funded by the U.S. Army. This marked the beginning of the UWGSP series systems that have contributed to medical imaging and computing. We are now completing UWGSP11, and UWGSP12 is in start-up. From UWGSP1 to UWGSP11, we have improved performance by a factor of 1,000 to 2,000; e.g., 512 × 512 complex 2D FFT took 9 seconds in the UWGSP1 compared with less than 10 ms today, and 512 × 512 affine warping took 7.5 seconds compared with 3.32 ms now. Amazingly, the basic hardware and software architecture remain the same. UWGSP1 was a very good platform for image processing and analysis. It was also effective in giving demonstrations—e.g., the real-time MRI multiplanar display. It was commercialized more as a microscopy workstation than as a radiology workstation. In the mid-1980s, regular PCs did not have the necessary speed or capacity in terms of memory, disk space, display resolution, and the number of monitors supported. However, the boundaries between PCs and workstations have become blurred since the mid-1990s. With the remarkable cost reduction and improvements in the CPU clock speed, memory capacity, network speeds, display, and user interface, PC-based radiology workstations can now compete successfully with the radiology workstation model. This work was inspired by the insight and constant encouragement of the late Dr. John W. Loop.

Numerical Libraries and Tools for Scalable Parallel Cluster Computing

For cluster computing to be effective within the scientific community it is essential that there are numerical libraries and programming tools available to application developers. Cluster computing may mean a cluster of heterogeneous components or hybrid architecture with some SMP nodes. This is clear at the high end, for example the latest IBM SP architecture, as well as in clusters of PC-based workstations. However, these systems may present very different software environments on which to build libraries and applications, and indeed require a new level of flexibility in the algorithms if they are to achieve an adequate level of performance. We will consider here the libraries and software tools that are already available and offer directions that might be taken in the light of cluster computing.

Feasibility of brain volumetric analysis and reconstruction of images by transfontanel three-dimensional ultrasound.

Based on the authors' experience with reconstruction of the heart using three-dimensional echocardiography, the authors assessed the feasibility of three-dimensional reconstruction of brain images using transfontanelle ultrasound in selected cases of infants with abnormal intracranial findings. A conventional 5-MHz ultrasound transducer inside a transducer holder was rotated 180 degrees around its vertical axis using a computer-controlled stepper motor to acquire multiple sequential cross-sections of the brain. The raw digital data of this three-dimensionally recorded dataset were transferred to a PC-based workstation for further analysis. The reconstruction of the three-dimensional brain images and volumetric analysis were undertaken using a new dedicated software capable of three-dimensional reconstruction and volumetric analysis (Echo-PAC-3D, version 1.2 Beta, GE Vingmed, Horton, Norway). The reconstruction of sequential slices from the stored three-dimensional data allowed the visualization of the epicortical extension and volumetric measurements of the focal ischemic infarction in the superior tempoparietal lobe in a 2-week-old newborn with a focal ischemic brain lesion. In other 2-week-old newborns, the extension and volume of a periventricular hemorrhage was visualized by three-dimensional reconstruction of coronal cross-sectional images from the acquired three-dimensional dataset. The three-dimensional reconstruction of the lateral ventricles allowed the three-dimensional visualization and estimation of ventricular dilatation in milliliters in an 8-week-old infant with hydrocephalus. Three-dimensional reconstruction of brain images and volume estimation of brain lesions and cavities by ultrasound may provide new insights into the morphology and extension of ultrasonographically visible brain lesions.

Softcopy interpretation of head and abdominal computed tomograms: comparison of 1024 × 768 to 2048 × 2048 monitors

The purpose of this study was to determine the accuracy of interpretation of computed tomograms (CT) on 1K × 1K PC-based review workstations used by clinicians, and compare them to 2K × 2K diagnostic workstations used by radiologists. We reviewed 733 CT examinations, of which 390 were head and 198 abdominal. All studies were first reviewed on the PC-based workstation, and the findings were compared to those from the diagnostic workstation that served as the control. In all, 167 head and 49 abdominal CTs were negative. Forty head CTs had incidental findings. Of the 364 positive studies, 215 were head CTs and 149 were abdominal CTs. Findings were not apparent on the PC-based monitor in 3 out of the positive head CT cases (1.4 %) and 3 out of the positive abdominal studies (2 %). The combined missed rate was 1.65 %, which we consider to be an acceptable error rate for review workstations.

Accuracy of digital imaging interpretation on an 1K × 1K PC-based workstation in the emergency department

The purpose of this study was to evaluate the accuracy of interpretation of digital radiographs on 1K × 1K PC-based workstations and compare it to that of 2K × 2K workstations in our filmless emergency department. We reviewed 1013 studies, of which 404 were chest, 133 abdominal, and 476 musculoskeletal. All studies were interpreted prospectively on the 1K × 1K workstation, and the findings were compared to those on the 2K × 2K diagnostic workstation which served as the control. Among all the studies performed, 515 were negative (255 chest, 91 abdominal, and 169 musculoskeletal). Another 498 had positive findings (149 chest, 42 abdominal, and 307 musculoskeletal). When the cases were reviewed on the 1K × 1K monitor, the diagnosis was missed in 5 of the 149 positive chest cases (3.35 %), in 5 of the 307 positive musculoskeletal cases (1.63 %), and in none of the 42 positive abdominal cases (0 %). In total, we misinterpreted 10 of the 498 positive cases (2.01 %). The miss rate of the 1K × 1K clinicians' review station is low and acceptable for its stated purpose. However, we doubt that it can be used for primary diagnostic purposes.

PC-based workstation for real-time acquisition, processing, and display of electromyogram signals

PC-based workstation for real-time acquisition, processing, and display of electromyogram signals

Linux update: an experimental ATM network

Both private and public networks increasingly use ATM to provide high bandwidth and guaranteed quality of service. The ability to use Linux in PC platforms and the ready availability of Linux source code make the PC-based Linux workstation an ideal platform for ATM multimedia development. This article describes some of Fujitsu's ATM tools for Linux and reports the results of prototyping using Fujitsu's ATM/Linux development environment.

A PC-based workstation for processing and analysis of MRI data.

The present work demonstrates that a low cost, flexible and user-friendly workstation for the MRI laboratory can be implemented by using a personal computer and public-domain software. The workstation is based on a Pentium personal computer, operating under the Linux operative system, and uses the software Khoros (Khoral Research, Albuquerque, NM). This software is a general purpose package for handling signals and we here report its suitability for MR images analysis. Khoros allows to create workspaces where different procedures (also written by the users) can be combined for implementing more complex procedures. We created workspaces for obtaining 2D and 3D images from time domain data which also allow for apodization and zero-filling. The time required for a 3D-FFT (matrix size 128x128x128) is about 12 min with the presently used microprocessor. We have also created workspaces for calculating apparent diffusion coefficient maps and for segmentation of MR images. Our results demonstrate that a personal computer equipped with public-domain software can represent a powerful tool to fulfil the MRI laboratory common needs.

A PC-based workstation for processing and analysis of MRI data

A PC-based workstation for processing and analysis of MRI data

World Wide Web interface for advanced SPECT reconstruction algorithms implemented on a remote massively parallel computer

Data from Single Photon Emission Computed Tomography (SPECT) studies are blurred by inevitable physical phenomena occurring during data acquisition. These errors may be compensated by means of reconstruction algorithms which take into account accurate physical models of the data acquisition procedure. Unfortunately, this approach involves high memory requirements as well as a high computational burden which cannot be afforded by the computer systems of SPECT acquisition devices. In this work the possibility of accessing High Performance Computing and Networking (HPCN) resources through a World Wide Web interface for the advanced reconstruction of SPECT data in a clinical environment was investigated. An iterative algorithm with an accurate model of the variable system response was ported on the Multiple Instruction Multiple Data (MIMD) parallel architecture of a Cray T3D massively parallel computer. The system was accessible even from low cost PC-based workstations through standard TCP/IP networking. A speedup factor of 148 was predicted by the benchmarks run on the Cray T3D. A complete brain study of 30 (64×64) slices was reconstructed from a set of 90 (64×64) projections with ten iterations of the conjugate gradients algorithm in 9 s which corresponds to an actual speed-up factor of 135. The technique was extended to a more accurate 3D modeling of the system response for a true 3D reconstruction of SPECT data; the reconstruction time of the same data set with this more accurate model was 5 min. This work demonstrates the possibility of exploiting remote HPCN resources from hospital sites by means of low cost workstations using standard communication protocols and an user-friendly WWW interface without particular problems for routine use.

High-performance computing and networking as tools for accurate emission computed tomography reconstruction.

It is well known that the quantitative potential of emission computed tomography (ECT) relies on the ability to compensate for resolution, attenuation and scatter effects. Reconstruction algorithms which are able to take these effects into account are highly demanding in terms of computing resources. The reported work aimed to investigate the use of a parallel high-performance computing platform for ECT reconstruction taking into account an accurate model of the acquisition of single-photon emission tomographic (SPET) data. An iterative algorithm with an accurate model of the variable system response was ported on the MIMD (Multiple Instruction Multiple Data) parallel architecture of a 64-node Cray T3D massively parallel computer. The system was organized to make it easily accessible even from low-cost PC-based workstations through standard TCP/IP networking. A complete brain study of 30 (64x64) slices could be reconstructed from a set of 90 (64x64) projections with ten iterations of the conjugate gradients algorithm in 9 s, corresponding to an actual speed-up factor of 135. This work demonstrated the possibility of exploiting remote high-performance computing and networking resources from hospital sites by means of low-cost workstations using standard communication protocols without particular problems for routine use. The achievable speed-up factors allow the assessment of the clinical benefit of advanced reconstruction techniques which require a heavy computational burden for the compensation effects such as variable spatial resolution, scatter and attenuation. The possibility of using the same software on the same hardware platform with data acquired in different laboratories with various kinds of SPET instrumentation is appealing for software quality control and for the evaluation of the clinical impact of the reconstruction methods.

Optimal display conditions for quantitative analysis of stereoscopic cerebral angiograms

For several years the authors have been using a stereoscopic display as a tool in the planning of stereotactic neurosurgical techniques. This PC-based workstation allows the surgeon to interact with and view vascular images in three dimensions, as well as to perform quantitative analysis of the three-dimensional (3-D) space. Some of the perceptual issues relevant to the presentation of medical images on this stereoscopic display were addressed in five experiments. The authors show that a number of parameters-namely the shape, color, and depth cue, associated with a cursor-as well as the image filtering and observer position, have a role in improving the observer's perception of a 3-D image and his ability to localize points within the stereoscopically presented 3-D image. However, an analysis of the results indicates that while varying these parameters can lead to an effect on the performance of individual observers, the effects are not consistent across observers, and the mean accuracy remains relatively constant under the different experimental conditions.

Direct on-line imaging and quantification of 8-12 bit digital image information for microscopy

In microscopy a digital pixel-accurate intensity processing (PAIP) technology for differential contrast enhancement became available for precise extraction and display of image information. Utilizing PC-based massively parallel processing at 1,600 million instructions per second (MIPS), the PAIP image enhancement can be performed on/off-line in near-real-time for objective image evaluation of 8-12 bit data.We used a PC-based workstation (PiXision PiX4: Visionary Systems Inc., New Haven, CT) on-line in combination with a JSM-890 FSEM (JEOL, Peabody, MA) as well as off-line with imported digital micrograph data and analyzed digital image contrast characteristics. The system provided automated intensity processing of any data independent of image content, size and depth. The images were first smoothed through averaging within a defined significant intensity range (IRs). Each pixel was provided with a variable automatically adjusting local averaging mask, generating a processing characteristic of non-linear point processing. Then, since the spacial processing was pixel-accurate (no spacial distortions of maintained intensity structures), all the contrast information eliminated by the smoothing could be recovered through subtraction of the smoothed from the original or previously smoothed data, followed by linear scaling to 8 bit.

A Noxious Agents Information System with State-wide Participation of the Public Health Service

With environmental health receiving increased attention by Public Health Services, there is a need to access as efficiently as possible detailed, current, and reliable information of physico-chemical, epidemiological, and toxicological as well as regulatory and legal aspects on this subject. Correspondingly, targets 19 and 35 of WHO's "Health for all 2000" strategy all for information systems to meet these demands. On this basis, a Noxious Agents Information System (NIS) was designed with three components: PC-based information workstations allowing access to portable and online databases; a dedicated modular database system providing "immediate answers" as well as support for more comprehensive information retrieval; and a cooperative network for training, information exchange, and consultation. During 1992-93, the system was introduced in Germany in the State of North Rhine-Westphalia, and 54 of 59 eligible institutions (92%) of the Public Health Service decided to participate, proving a virtually state-wide introduction to be feasible. Details are presented of the NIS concept and its realization, and limitations and future perspectives are discussed.

Flexible PC-based workstation for auditory evoked potential and psychoacoustic experiments.

Flexible PC-based workstation for auditory evoked potential and psychoacoustic experiments.

Fast reasoning with external data on personal computers

Possible ways of speeding-up the inference cycle of inference engines capable of reasoning with external data are studied in this paper. The design and implementation of such inference engines on personal computers and PC-based workstations are illustrated by a description of FLEXIE, a PC-based inference engine. FLEXIE has been developed as an integral part of FLEX, a prototype real-time expert system shell for personal computers. The FLEX shell is briefly reviewed in the paper, and FLEXIE is examined in detail. A fast pattern-matcher, based on the RETE algorithm, is built into FLEXIE. During the pattern-matching phase, FLEXIE communicates with FLEXEN, the FLEX interface to the environment, in order to include external information into the reasoning process. The design of the pattern-matching algorithm makes it suitable for hardware implementation, which can make the pattern-matching process run considerably faster. An architecture for such a hardware pattern-matcher is proposed, and initial simulation results are presented. Two possibilities for concurrent implementation of the inference cycle are used in the design of the hardware pattern-matcher. The contribution of parallelism to the pattern-matching speed-up is also discussed. Simulation shows the overall speed-up to be more than an order of magnitude.