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At least 721 records · Page 40Linked to original sources
PubMed2006

Rate-distortion optimized hybrid error control for real-time packetized video transmission.

The problem of application-layer error control for real-time video transmission over packet lossy networks is commonly addressed via joint source-channel coding (JSCC), where source coding and forward error correction (FEC) are jointly designed to compensate for packet losses. In this paper, we consider hybrid application-layer error correction consisting of FEC and retransmissions. The study is carried out in an integrated joint source-channel coding (IJSCC) framework, where error resilient source coding, channel coding, and error concealment are jointly considered in order to achieve the best video delivery quality. We first show the advantage of the proposed IJSCC framework as compared to a sequential JSCC approach, where error resilient source coding and channel coding are not fully integrated. In the USCC framework, we also study the performance of different error control scenarios, such as pure FEC, pure retransmission, and their combination. Pure FEC and application layer retransmissions are shown to each achieve optimal results depending on the packet loss rates and the round-trip time. A hybrid of FEC and retransmissions is shown to outperform each component individually due to its greater flexibility.

Algorithms↗
PubMed1996

Virtual resource development in the glycosciences.

The development of Internet-based virtual resources is a relatively new area of scientific and technical activity that is currently undergoing rapid expansion. Major factors fuelling recent growth include the emergence of multimedia capabilities through the rapid evolution of the World Wide Web, the reduction in cost of high quality personal computers and graphics workstations and the provision of mass-marketed provider services. Prior to 1995 the presence of Internet resources in the glycosciences was virtually non-existent. Existing scientific knowledge was primarily made available on the Net through the provision of databases from gopher and ftp sites. A particular example in the glycosciences is the Carbbank database of biological carbohydrate sequences. We will describe here our efforts in 1994-95 in establishing The Glycoscience Network (TGN, http:@ bellatrix.pcl.ox.ac.uk/TGN/). These activities included the establishment of a newsgroup, mailing lists, Web resources and the running of the First Electronic Glycoscience Conference (EGC-1, http:@bellatrix.pcl.ox.ac.uk/egc/). EGC-1 included many novel initiatives in the glycosciences including electronic posters and papers, a Virtual Conference Centre, a Web-based hyperglossary, Virtual Trade and Employment Centres, refereed electronic publishing, and the creation of a Virtual Reality Gallery. We would like to look towards the near future and discuss several initiatives in virtual resource creation that we believe will have significant scientific impact on the glycosciences including the development of bioinformatics-based servers, sophisticated interactive databases, and videoconferencing. Furthermore, we cherish the belief that these resources will foster international scientific collaboration and progress of an extent never previously possible. Finally, we indulge in speculation and make some suggestions on the form and long-term impact of Glycoscience Virtual Resources. We predict that their development may completely reconstruct the scientific environment that we work in as scientists and we reflect on the probable benefits and pitfalls to be encountered.

Carbohydrates↗
PubMed2004

A wireless PDA-based physiological monitoring system for patient transport.

This paper proposes a mobile patient monitoring system, which integrates current personal digital assistant (PDA) technology and wireless local area network (WLAN) technology. At the patient's location, a wireless PDA-based monitor is used to acquire continuously the patient's vital signs, including heart rate, three-lead electrocardiography, and SpO2. Through the WLAN, the patient's biosignals can be transmitted in real-time to a remote central management unit, and authorized medical staffs can access the data and the case history of the patient, either by the central management unit or the wireless devices. A prototype of this system has been developed and implemented. The system has been evaluated by technical verification, clinical test, and user survey. The evaluation of performance yields a high degree of satisfaction (mean = 4.64, standard deviation--SD = 0.53 in a five-point Likert scale) of users who used the PDA-based system for intrahospital transport. The results also show that the wireless PDA model is superior to the currently used monitors both in mobility and in usability, and is, therefore, better suited to patient transport.

Adult↗
PubMed2005

Blind information-theoretic multiuser detection algorithms for DS-CDMA and WCDMA downlink systems.

Code division multiple access (CDMA) is based on the spread-spectrum technology and is a dominant air interface for 2.5G, 3G, and future wireless networks. For the CDMA downlink, the transmitted CDMA signals from the base station (BS) propagate through a noisy multipath fading communication channel before arriving at the receiver of the user equipment/mobile station (UE/MS). Classical CDMA single-user detection (SUD) algorithms implemented in the UE/MS receiver do not provide the required performance for modern high data-rate applications. In contrast, multi-user detection (MUD) approaches require a lot of a priori information not available to the UE/MS. In this paper, three promising adaptive Riemannian contra-variant (or natural) gradient based user detection approaches, capable of handling the highly dynamic wireless environments, are proposed. The first approach, blind multiuser detection (BMUD), is the process of simultaneously estimating multiple symbol sequences associated with all the users in the downlink of a CDMA communication system using only the received wireless data and without any knowledge of the user spreading codes. This approach is applicable to CDMA systems with relatively short spreading codes but becomes impractical for systems using long spreading codes. We also propose two other adaptive approaches, namely, RAKE -blind source recovery (RAKE-BSR) and RAKE-principal component analysis (RAKE-PCA) that fuse an adaptive stage into a standard RAKE receiver. This adaptation results in robust user detection algorithms with performance exceeding the linear minimum mean squared error (LMMSE) detectors for both Direct Sequence CDMA (DS-CDMA) and wide-band CDMA (WCDMA) systems under conditions of congestion, imprecise channel estimation and unmodeled multiple access interference (MAI).

Algorithms↗
PubMedDate not supplied

Success with Web-based image access.

The University of Mississippi Medical Center in Jackson, Miss., is the only medical school in the state. We performed 235,000 procedures in the 2001-02 fiscal year. All imaging services within the radiology department are networked to a PACS and are filmless. The elimination of film required that we decentralize our traditional file room to allow easy access to our radiology network across the campus. In our facility, there are three levels of image access: Diagnostic Quality, Review Quality and Web Access. Diagnostic Quality requires top-of-the-line workstations and monitors and is the most expensive. Review Quality workstations represent some savings over Diagnostic and are used in the ICU, orthopedics and surgery. Web Access appears to satisfy most areas outside the main diagnostic department. The account set-up procedure is simple because it uses our intranet email system. Images are easily pasted into presentation applications for articles and conferences. However, the main advantage of Web Access is the low cost. The downside of Web Access is that the images are for review only and are limited by the quality of the monitor in use. It is also somewhat cumbersome to retrieve old or comparison images via this method. The Web only holds approximately 45 days of the most recent images, therefore older studies may not be available. The deployment of this Web-based service has aided in our efforts to reduce the amount of film we print and has also been beneficial in improving patient care through faster service.

Computer Communication Networks↗
PubMed2006

eHealth Literacy: Essential Skills for Consumer Health in a Networked World.

Electronic health tools provide little value if the intended users lack the skills to effectively engage them. With nearly half the adult population in the United States and Canada having literacy levels below what is needed to fully engage in an information-rich society, the implications for using information technology to promote health and aid in health care, or for eHealth, are considerable. Engaging with eHealth requires a skill set, or literacy, of its own. The concept of eHealth literacy is introduced and defined as the ability to seek, find, understand, and appraise health information from electronic sources and apply the knowledge gained to addressing or solving a health problem. In this paper, a model of eHealth literacy is introduced, comprised of multiple literacy types, including an outline of a set of fundamental skills consumers require to derive direct benefits from eHealth. A profile of each literacy type with examples of the problems patient-clients might present is provided along with a resource list to aid health practitioners in supporting literacy improvement with their patient-clients across each domain. Facets of the model are illustrated through a set of clinical cases to demonstrate how health practitioners can address eHealth literacy issues in clinical or public health practice. Potential future applications of the model are discussed.

Computer Communication Networks↗
PubMed1998

Secured medical imaging over the Internet.

The Internet has established itself as an affordable, extremely viable and ubiquitous communications network that can be easily accessed from virtually any point in the world. This makes it ideally suited for medical image communications. Issues regarding security and confidentiality of information on the Internet, however, need to be addressed for both occasional, individual users and consistent enterprise-wide users. In addition, the limited bandwidth of most Internet connections must be factored into the development of a realistic usermodel and resulting protocol. Open architecture issues must also be considered so that images can be communicated to recipients who do not have similar programs. Further, application-specific software is required to integrate image acquisition, encryption and transmission into a single, streamlined process. Using Photomailer software provided by PhysiTel Inc., the authors investigated the use of sending secured still images over the Internet. The scope of their investigation covered the use of the Internet for communicating images for consultation, referral, mentoring and education. Photomailer software was used at several local and remote sites. The program was used for both sending and receiving images. It was also used for sending images to recipients who did not have Photomailer, but instead relied on conventional email programs. The results of the investigation demonstrated that using products such as Photomailer, images could be quickly and easily communicated from one location to another via the Internet. In addition, the investigators were able to retrieve images off of their existing email accounts, thereby providing greater flexibility and convenience than other systems which require scheduled transmission of information on dedicated systems. We conclude that Photomailer and similar products may provide a significant benefit and improve communications among colleagues, providing an inexpensive means of sending secured images on the Internet.

Computer Communication Networks↗
PubMed1996

Information-seeking behavior of health professionals in Hong Kong: a survey of thirty-seven hospitals.

Shortly after the establishment of Hong Kong's Hospital Authority (HA) in 1990, ten library service networks supported by the Library Information Systems (HALIS) were established to pool resources. A survey was undertaken to investigate the information-seeking behavior of health professionals working in thirty-seven public hospitals, examine their information needs, assess user satisfaction with and the impact of library services (including HALIS), and examine why hospital libraries sometimes fail to meet user needs. The findings revealed disparate use patterns among different groups of health professionals and confirmed that medical staff were most satisfied with the library collections and services. The nurses and hospital executives were found to be underserved. They needed information not only for work-related reasons but also to support self-study and development. The new HALIS service was neither well known nor widely used, especially among nurses. The findings provided valuable measures of performance for comparing different hospitals and assessing changes over time. Survey results also highlighted areas in which improvements are needed, such as collection enhancement, promotion and user training, and assessment of the impact of library service on patient care. Subsequent developments in these directions have led to increased awareness and use of library services and confirmed the direction of strategic plans for growth.

CD-ROM↗
PubMed1997

The Internet and electronic transmission of medical records.

OBJECTIVE: To review, from a legal perspective the potential for using the Internet for inter-institutional transfer of patient medical records. METHODS: Basic issues and recent legislation that relate to protection of both medical data, and those transferring that data over public network systems is reviewed. RESULTS: Many laws already in existence can be applied to Internet transmission, but questions of jurisdiction remain. Providing signatures on requests for information, which are in essence contracts, is a problem. Signatures must both prove the identity of the participants and provide for non-repudiation of the agreement. Cryptographic digital signatures appear secure and effective, but their use is difficult to implement. Simpler methods are fraught with risks, yet are more easily accomplished. The patient's rights of privacy must be balanced against the need for access by government, physician, or healthcare institutions to confidential information. In general, information holders must put forth reasonable efforts to keep information confidential. The development of acknowledged standards will provide guidance. Multiple laws provide some deterrence and hence some reassurance to healthcare institutions, for example, by criminalizing acts of electronic interception of patient records in transit. CONCLUSION: Some believe the expense of secure transfer of medical records by electronic means is a major obstacle; this is false: such transfers are now technologically quite easy. The greatest obstacle to electronic transfer of medical records at this point is the development of workable standards for signing agreements and protecting transmissions, but the perceived advantages will likely drive the necessary developments.

Computer Communication Networks↗
PubMed2006

Reducing video-quality fluctuations for streaming scalable video using unequal error protection, retransmission, and interleaving.

Forward error correction based multiple description (MD-FEC) transcoding for transmitting embedded bitstream over the packet erasure networks has been extensively studied in the past. In the existing work, a single embedded source bitstream, e.g., the bitstream of a group of pictures (GOP) encoded using three-dimensional set partitioning in hierarchical trees is optimally protected unequal error protection (UEP) in the rate-distortion sense. However, most of the previous work on transmitting embedded video using MD-FEC assumed that one GOP is transmitted only once, and did not consider the chance of retransmission. This may lead to noticeable video quality variations due to varying channel conditions. In this paper, a novel window-based packetization scheme is proposed, which combats bursty packet loss by combining the following three techniques: UEP, retransmission, and GOP-level interleaving. In particular, two retransmission mechanisms, namely segment-wise retransmission and byte-wise retransmission, are proposed based on different types of receiver feedback. Moreover, two levels of rate allocations are introduced: intra-GOP rate allocation minimizes the distortion of individual GOP; while inter-GOP rate allocation intends to reduce video quality fluctuations by adaptively allocating bandwidth according to video signal characteristics and client buffer status. In this way, more consistent video quality can be achieved under various packet loss probabilities, as demonstrated by our experimental results.

Algorithms↗
PubMed1999

Legal issues concerning electronic health information: privacy, quality, and liability.

Personally identifiable health information about individuals and general medical information is increasingly available in electronic form in health databases and through online networks. The proliferation of electronic data within the modern health information infrastructure presents significant benefits for medical providers and patients, including enhanced patient autonomy, improved clinical treatment, advances in health research and public health surveillance, and modern security techniques. However, it also presents new legal challenges in 3 interconnected areas: privacy of identifiable health information, reliability and quality of health data, and tortbased liability. Protecting health information privacy (by giving individuals control over health data without severely restricting warranted communal uses) directly improves the quality and reliability of health data (by encouraging individual uses of health services and communal uses of data), which diminishes tort-based liabilities (by reducing instances of medical malpractice or privacy invasions through improvements in the delivery of health care services resulting in part from better quality and reliability of clinical and research data). Following an analysis of the interconnectivity of these 3 areas and discussing existing and proposed health information privacy laws, recommendations for legal reform concerning health information privacy are presented. These include (1) recognizing identifiable health information as highly sensitive, (2) providing privacy safeguards based on fair information practices, (3) empowering patients with information and rights to consent to disclosure (4) limiting disclosures of health data absent consent, (5) incorporating industry-wide security protections, (6) establishing a national data protection authority, and (7) providing a national minimal level of privacy protections.

Computer Communication Networks↗
PubMed1997

The digital anatomist information system and its use in the generation and delivery of Web-based anatomy atlases.

Advances in network and imaging technology, coupled with the availability of 3-D datasets such as the Visible Human, provide a unique opportunity for developing information systems in anatomy that can deliver relevant knowledge directly to the clinician, researcher or educator. A software framework is described for developing such a system within a distributed architecture that includes spatial and symbolic anatomy information resources, Web and custom servers, and authoring and end-user client programs. The authoring tools have been used to create 3-D atlases of the brain, knee and thorax that are used both locally and throughout the world. For the one and a half year period from June 1995-January 1997, the on-line atlases were accessed by over 33,000 sites from 94 countries, with an average of over 4000 "hits" per day, and 25,000 hits per day during peak exam periods. The atlases have been linked to by over 500 sites, and have received at least six unsolicited awards by outside rating institutions. The flexibility of the software framework has allowed the information system to evolve with advances in technology and representation methods. Possible new features include knowledge-based image retrieval and tutoring, dynamic generation of 3-D scenes, and eventually, real-time virtual reality navigation through the body. Such features, when coupled with other on-line biomedical information resources, should lead to interesting new ways for managing and accessing structural information in medicine.

Anatomy↗
PubMed2000

Relevance of mandates, notifications and threads in the management of continuity of care.

Availability of electronic healthcare records (EHCR) and geographical networks allows nowadays to realise a set of functionalities to support continuity of care. Actual exchange of complete clinical information, common centralised records, common decisions within an agreed protocols are not mandatory. Sub-optimal alternatives, involving easier management, are possible. In fact, the crucial challenge for continuity of care is the mutual awareness of the multiple perspectives by the actors contributing to patient's care. The various actors should timely know changes in the status of: mandates, i.e. who is involved in the care provision and thus is responsible for a "local" record. knowledge about the patient, i.e. active and inactive problems, impressions, relevant findings. provision of healthcare activities, i.e. plans, orders and performed activities. The decisions on the actual implementation depend on the healthcare context, as implemented within the information system. For example, the mechanism for notifications involves decisions on the quality and quantity of information that must be exchanged, as well as on the modalities for the exchange, regulated by individual user's profiles. Each notification could be sent as a message to a central repository, and then each authorized user could select within the repository the pertaining messages. Or a notification could be sent directly to the list of professionals involved in the care of a patient, that asked for it in their profile. Mandates may be used to regulate the access of the users to the patient's information. This approach was embedded in a European standard under development in CEN/TC251 (CONTSYS--"System of concepts to support continuity of care").

Computer Communication Networks↗
PubMedDate not supplied

MATCH: a maternal and child health information network.

The Maternal and Child Health Information Network--MATCH--was begun in 1984 as a demonstration project with support from the Division of Maternal and Child Health of the Health Resources and Services Administration, Public Health Service. The primary purpose of the project was the development of a system to manage data related to prenatal, child health, family planning, and genetic services that are delivered with State support in clinics in the State of Ohio. The design of MATCH enables the same data base to be used at both the State and local levels. Because it allows all participants, central and district, to manipulate the raw data, it is called an end-user--as opposed to a batch retrieval--system. Data recorded on individual forms during each client's visit to local service clinics are collected and entered into a microcomputer whose software package is a commercial data base. The clinic can then use the data for its purposes: program planning, management, evaluation, client referrals, appointment followup, quality control, and billing. The same data are also uploaded by central office staff to the State's DEC mainframe from data-filled disks mailed in by the clinics. Personnel who staff local projects can access their own data on the mainframe computer to generate reports for local use and send and receive messages electronically. That is, the system is "interactive." The intent is to first link data generated by the primary care and preventive programs of maternal and child health (MCH) in an information system,then link that system to other health data arriving at the State health department (for example, birth and death certificates), and, finally, to use the system as the basis for a State level MCH primary care data system in Ohio for surveillance, planning,management, quality control, accountability,and research purposes.

Child Health Services↗
PubMed2001

Independent checking of the delivered dose for high-energy X-rays using a hand-held PC.

BACKGROUND AND PURPOSE: The requirements on the delivered dose in radical radiation therapy are extremely high. The dose should be within a few percent and also delivered with high accuracy in space. Vendors and users have successfully managed to implement radiation therapy systems, which are able to achieve these demands with high accuracy and reproducibility. These systems include computerized tomography scanners, treatment planning systems, simulators, treatment machines, and record and verify systems. More and more common are also computer networks to assure data integrity when transferring information between the systems. Even if these systems are commissioned and kept under quality assurance programs to maintain their accuracy, errors may be introduced. Especially, the human factor is an uncontrolled parameter that may introduce errors. Thus, unintentional changes or incorrect handling of data may occur during clinical use of the equipment. Having an independent dose calculation system implemented in the daily quality assurance process may assure a high quality of treatments and avoidance of severe errors. MATERIALS AND METHODS: To accomplish this, a system of equations for calculating the absorbed dose to the prescription point from the set-up information, has been compiled into a dose-calculation engine. The model is based on data completely independent of the treatment planning system (TPS). The fundamental parameter in the dose engine is the linear attenuation coefficient for the primary photons. This parameter can readily be determined experimentally. The dose calculation engine has been programmed into a hand-held PC allowing direct calculation of the dose to the prescription point when the first treatment is delivered to the patient. RESULTS AND CONCLUSION: The model is validated with measurements and is shown to be within +/-1.0% (1 SD). Comparison against a state-of-the-art TPS shows an average difference of 0.3% with a standard deviation of +/-2.1%. An action level covering 95% of the cases has been chosen, i.e. +/-4.0%. Deviations larger than this are with a high probability due to erroneous handling of the patient set-up data. This system has been implemented into the daily clinical quality control program.

Algorithms↗
PubMed2001

Remote sonographic interpretation using a laser printer network: system performance and diagnostic accuracy in actual clinical practice.

OBJECTIVE: The purpose of our study was to evaluate the technical and clinical performance of remote sonographic interpretation using a laser printer network connecting a community-based imaging center and an academic medical center. SUBJECTS AND METHODS: During a 3-month period, 161 consecutive sonographic examinations were performed at a community-based imaging center and all 161 patients were enrolled in the study. Seventy-one (44%) of 161 examinations were interpreted on-site at the community-based imaging center, and 90 (56%) of 161 were transmitted over a T-1 line to an academic medical center where the static images were interpreted remotely. For the purposes of this study, the examination time was defined as the interval from the time the technologist started to scan the patient to the time the patient was dismissed from the radiology department. Examination times were recorded for each patient. Follow-up was available for 92 (57%) of 161 studies. Sensitivity and specificity for studies interpreted at the community-based imaging center and at the academic medical center were calculated. RESULTS: The mean examination time for pelvic sonographic examinations interpreted at the academic medical center (43 min) was significantly longer than for scans interpreted at the community-based imaging center (31 min) (p < 0.01). However, no significant difference was noted in the examination time for abdominal sonography. For all examinations interpreted on-site at the community-based imaging center for which follow-up was available, the sensitivity and specificity were 95% and 100%, respectively. For all examinations interpreted remotely at the academic medical center for which follow-up was available, the sensitivity and specificity were 93% and 90%, respectively. No significant difference was seen in the sensitivity (p = 1.00) or specificity (p = 0.24) of studies interpreted on-site versus remotely. CONCLUSION: Static sonographic images can be interpreted remotely without loss of sensitivity, but with decreased specificity. However, more time must be allotted for performing pelvic sonography when these examinations are to be interpreted remotely.

Abdomen↗
PubMed1996

The use of E-mail by otolaryngologists.

Electronic mail (e-mail) is an extremely powerful form of communication and the most frequently used application on the Internet. While e-mail is not the appropriate mode of communication for every situation, there are many instances where its use is invaluable.

Communication↗