Online Guidance Research Articles

Mars Atmospheric Entry Guidance Design by Sliding Mode Disturbance Observer-Based Control

One of the demands for future Mars exploration is pin-point landing, in which the landing precision should be less than one hundred meters and is two orders of magnitude higher than the current level. In the process of the high-speed vehicle entering a rarefied atmosphere with highly uncertainties as the Mars atmosphere, the trajectory deviation caused by entry guidance can be the major part of the total landing errors. Due to modeling errors such as the atmospheric modeling error and the vehicle's aerodynamic model inaccuracy, the more the guidance law depends on the models, the larger the trajectory dispersion can be. To reduce the impact of model errors on guidance performance, a guidance law based on the second-order sliding mode variable structure control is developed for reference trajectory tracking. The guidance law which is tested in a real entry scenario is proved to be evident in reducing the control gain and the requirement for control ability. The proposed guidance law also shows accurate tracking for the reference trajectory and high precision of the landing sites, and thus has the potential to be applied to online guidance.

Five-year follow-up using a prostate stent as fiducial in image-guided radiotherapy of prostate cancer

Purpose. To report results from the five-year follow-up on a previously reported study using image-guided radiotherapy (IGRT) of localized or locally advanced prostate cancer (PC) and a removable prostate stent as fiducial.Material and methods. Patients with local or locally advanced PC were treated using five-field 3D conformal radiotherapy (3DRT). The clinical target volumes (CTV) were treated to 78 Gy in 39 fractions using daily on-line image guidance (IG). Late genito-urinary (GU) and gastro-intestinal (GI) toxicities were scored using the radiotherapy oncology group (RTOG) score and the common toxicity score of adverse events (CTC) score. Urinary symptoms were also scored using the international prostate symptom score (IPSS).Results. Median observation time was 5.4 year. Sixty-two of the 90 patients from the original study cohort were eligible for toxicity assessment. Overall survival, cancer-specific survival and biochemical freedom from failure were 85%, 96% and 80%, respectively at five years after radiotherapy. Late toxicity GU and GI RTOG scores ≥ 2 were 5% and 0%. Comparing pre- and post-radiotherapy IPSS scores indicate that development in urinary symptoms after radiotherapy may be complex.Conclusions. Prostate image-guided radiotherapy using a prostate stent demonstrated survival data comparable with recently published data. GU and GI toxicities at five-year follow-up were low and comparable to the lowest toxicity rates reported. These findings support that the precision of the prostate stent technique is at least as good as other techniques. IPSS revealed a complex development in urinary symptoms after radiotherapy.

A nationwide telepathology consultation and quality control program in China: implementation and result analysis.

BackgroundTelepathology may play an important role in pathology consultation and quality control for cancer diagnosis in China, as the country has the largest population of cancer patients worldwide. In 2011, the Pathology Quality Control Center of China and Ministry of Health developed and implemented a nationwide telepathology consultation and quality control program for cancer diagnosis in China. We here report the results of the two-year implementation and experiences.Methodsthe program built an Internet based telepathology platform to connect participating hospitals and expert consultants. The hardware and software used for the platform were validated in previous validation studies in China. The program had three regional centers consisting of Peking Union Medical College, Huasi Medical College of Sichuan and 2nd affiliated hospital of Zhejiang University. It also had 20 provincial consultation centers based in the provincial referral hospitals. 80 provincial or national pathologists served as expert consultants for the program, providing telepathology consultation for cancer diagnosis for more than 60 participating hospitals.Resultsfrom 2011 to July 2013, 16,247 pathology cases were submitted to the platform for consultation. Among them, 84% were due to diagnostic difficulty and 16% were due to request by patients. The preliminary diagnosis provided by submitting pathologists were in agreement with expert opinion in 59.8% of cases but was in disagreement with expert opinion in 24.2% of cases. 16.0% of cases were not provided with preliminary diagnosis. The distribution of pathology cases by system or organ were: digestive system, 17.3%; gynecologic system, 16.7%; head and neck, 15.7%; bone and soft tissue, 10.4%; lung and mediastinum, 8.6%; breast, 7.6%; urinary system, 7.5%; hematopathology, 6.4%; skin, 5.2%; neuropathology, 2.5% and cytopathology, 1.3%. Expert consultants also provided assessment of quality of slide preparation and staining, online lectures and guidance for pathology quality control.Conclusionour results of two years' implementation indicated that telepathology could solve the problem of uneven distribution of pathology resources and provide a solution for countrywide pathology quality control in China. Telepathology could play an important role in improving pathology diagnosis in China.

Recommendations for Prostate Cancer Survivorship Care: An Update to the 2009 Michigan Cancer Consortium Guidelines for the Primary Care Management of Prostate Cancer Post-Treatment Sequelae

Background: Primary care providers inevitably care for prostate cancer survivors. However, few comprehensive resources exist to aid them in providing the most up-to-date and evidence-based care. To meet this clinical need, we examined and updated the Michigan Cancer Consortium prostate cancer survivorship guidelines. Methods: Using an expert panel and focus groups comprised of prostate cancer stakeholders, we updated the Michigan Cancer Consortium's 2009 Guidelines for the Primary Care Management of Prostate Cancer Post-Treatment Sequelae. Results: The guideline recommendations were modified to serve as a point-of-care resource and to facilitate care transitions between specialty and primary care. The modified recommendations were approved by the Michigan Cancer Consortium and now include the following elements: (1) patient-reported symptom assessment, (2) distinctions between medical and self-management strategies for prostate cancer treatment-related side effects, (3) recommendations for involving partners in survivorship care, and (4) care coordination strategies for primary and specialty care providers. Online guidance for medical therapy and self-management resources are also provided. Conclusions: To remedy a persistent lack of guidance to direct prostate cancer survivorship care in the primary care setting, the updated Michigan Cancer Consortium prostate cancer survivorship tools convert a static guideline into a dynamic resource to improve outcomes and support coordination among primary care providers, cancer specialists, patients, and caregivers.

Look where you’re going! Perceptual attention constrains the online guidance of action

Action guidance, like perceptual discrimination, requires selective attention. Perception is enhanced at the target of a reaching movement, but it is not known whether selecting an object for perception reciprocally prioritises it for action. Two theoretical frameworks, the premotor theory and the Visual Attention Model, predict that this reciprocal relation should hold. We tested the influence of perceptual attention on the online control of reaching. In Experiment 1, participants attended covertly to a flanker on one or other side of a fixated target, prior to reaching for that target, which occasionally jumped, after reach onset, to the attended or non-attended side. Participants corrected their reaches for almost all target jumps. In Experiment 2, we required covert monitoring of the flanker during reaching. This concurrent perceptual task globally reduced correction behaviour, indicating that perception and action share a common attentional resource. Corrections were especially unlikely toward the attended side. This is explained by assuming that perceptual attention primed an action toward the attended location and that the participant inhibited this primed action. The data thus imply that perceptual selection constrains online action guidance, as predicted by the premotor theory and the VAM. We further argue that the fact that participants can inhibit a location within the action system but simultaneously maintain its prioritisation for perceptual monitoring, is easier to reconcile with the VAM than with the premotor theory.

SU-D-16A-06: Modeling Biological Effects of Residual Uncertainties For Stereotactic Radiosurgery

Purpose: Residual uncertainties on the order of 1-2 mm are frequently observed when delivering stereotactic radiosurgery via on-line imaging guidance with a relocatable frame. In this study, a predictive model was developed to evalute potentiral late radiation effects associated with such uncertainties. Methods: A mathematical model was first developed to correlate the peripherial isodose volume with the internal and/or setup margins for a radiosurgical target. Such a model was then integrated with a previoulsy published logistic regression normal tissue complication model for determining the symptomatic radiation necrosis rate at various target sizes and prescription dose levels. The model was tested on a cohort of 15 brain tumor and tumor resection cavity patient cases and model predicted results were compared with the clinical results reported in the literature. Results: A normalized target diameter (D{sub 0}) in term of D{sub 0} = 6V/S, where V is the volume of a radiosurgical target and S is the surface of the target, was found to correlate excellently with the peripheral isodose volume for a radiosurgical delivery (logarithmic regression R{sup 2} > 0.99). The peripheral isodose volumes were found increase rapidly with increasing uncertainties levels. In general, a 1-mm residual uncertainties as calculated to resultmore » in approximately 0.5%, 1%, and 3% increases in the symptomatic radiation necrosis rate for D{sub 0} = 1 cm, 2 cm, and 3 cm based on the prescription guideline of RTOG 9005, i.e., 21 Gy to a lesion of 1 cm in diameter, 18 Gy to a lesion 2 cm in diameter, and 15 Gy to a lesion 3 cm in diameter respectively. Conclusion: The results of study suggest more stringent criteria on residual uncertainties are needed when treating a large target such as D{sub 0}≤ 3 cm with stereotactic radiosurgery. Dr. Ma and Dr. Sahgal are currently serving on the board of international society of stereotactic radiosurgery (ISRS)« less

Building capacity to measure long-term impact on women's empowerment: CARE's Women's Empowerment Impact Measurement Initiative

From 2010 to 2012, CARE USA implemented the Women's Empowerment Impact Measurement Initiative (WEIMI) to develop the necessary capacity, tools, guidance, and practice to measure and demonstrate the impact of its work on women's empowerment. The lessons and experiences from this initiative have been transformed into an online guidance tool being utilised throughout CARE to inform the process of developing robust theories of change and impact measurement systems for women's empowerment programmes. The WEIMI experience has contributed significantly to CARE's understanding of gender inequality and its implications for achieving broader impact. This article highlights key lessons learned and good practices that emerged in addressing the challenge of developing organisational impact measurement systems for women's empowerment long-term programmes.

On-line optimal autonomous reentry guidance based on improved Gauss pseudospectral method

The on-line optimal autonomous reentry guidance of the hypersonic vehicle is proposed based on the improved Gauss pseudospectral method (IGPM). The autonomous reentry guidance requires the hypersonic vehicle can generate the optimal trajectory for the latest flight mission on line and track the new trajectory well under the uncertainty. These two problems are simplified into a nonlinear optimal control problem with nonlinear constraints. The IGPM is introduced to solve the above two problems. The trajectory has to change according to the flight mission and therefore the new optimal trajectory can be obtained by IGPM within about 10 s. The optimal feedback guidance law is used to track the reference trajectory to handle the uncertainty. In order to deal with the CPU time delay, which comes from optimizing the new trajectory, the new on-line optimal autonomous reentry guidance is depicted. Finally, the numerical simulation shows that the proposed autonomous guidance can generate optimal trajectory for the new flight mission and have a high tracking accuracy.

Impact of body-mass factors on setup displacement in patients with head and neck cancer treated with radiotherapy using daily on-line image guidance

BackgroundTo determine the impact of body-mass factors (BMF) before radiotherapy and changes during radiotherapy on the magnitude of setup displacement in patients with head and neck cancer (HNC).MethodsThe clinical data of 30 patients with HNC was analyzed using the alignment data from daily on-line on-board imaging from image-guided radiotherapy. BMFs included body weight, body height, and the circumference and bilateral thickness of the neck. Changes in the BMFs during treatment were retrieved from cone beam computed tomography at the 10th and 20th fractions. Setup errors for each patient were assessed by systematic error (SE) and random error (RE) through the superior-inferior (SI), anterior-posterior (AP), and medial-lateral (ML) directions, and couch rotation (CR). Using the median values of the BMFs as a cutoff, the impact of the factors on the magnitude of displacement was assessed by the Mann–Whitney U test.ResultsA higher body weight before radiotherapy correlated with a greater AP-SE (p = 0.045), SI-RE (p = 0.023), and CR-SE (p = 0.033). A longer body height was associated with a greater SI-RE (p = 0.002). A performance status score of 1 or 2 was related to a greater AP-SE (p = 0.043), AP-RE (p = 0.015), and SI-RE (p = 0.043). Among the ratios of the BMFs during radiotherapy, the values at the level of mastoid tip at the 20th fraction were associated with greater setup errors.ConclusionsTo reduce setup errors in patients with HNC receiving RT, the use of on-line image-guided radiotherapy is recommended for patients with a large body weight or height, and a performance status score of 1–2. In addition, adaptive planning should be considered for those who have a large reduction ratio in the circumference (<1) and thickness (<0.94) over the level of the mastoid tip during the 20th fraction of treatment.

Expanding Online Guidance: Creating a Consumer-oriented Website with Practical Solutions for Healthy Eating on a Budget

Expanding Online Guidance: Creating a Consumer-oriented Website with Practical Solutions for Healthy Eating on a Budget

FRI0571-PC Primary care guidance for immunology testing in rheumatology: need and impact

BackgroundGuidelines in a tertiary care Rheumatology setting showed a reduction in unnecessary immunology testing, improving efficiency and reducing expenditure (1).ObjectivesTo assess the need for guidance for general practitioners (GPs) requesting...

The Impact Of Changing Technology: The Case Of E-Learning

For centuries, education has relied on classroom methods, but technology-enhanced learning can potentially bring about a revolution in learning, making high-quality, cost-effective education available to a greater number of people. The basic advantages of e-learning include anytime-anywhere access to learning, cost reductions, ability to reach larger markets, more effective learning with personalized instructions, and flexibility. For the full potential of e-learning to be realized, however, the content, services, and systems from different suppliers all need to work together. This paper provides an overview of the benefits and limitations of e-learning as well as its cost-effectiveness. The continual advances in information technology as well as software-based training and education are rapidly offering a cost-effective and flexible alternative to traditional face-to-face learning. With the introduction of e-learning, students are empowered to embark on active, independent learning. They can access course information and perform research with the help of this virtual space provided using the Internet. Consistency, fast deployment, and simple evaluation are all attractive features of e-learning, but the most compelling reason to consider the introduction of e-learning may be the significant reduction in costs associated with education. Once developed, the online guidance component can be used many times with minimal costs. Students can also go through the training process repeatedly to ensure maximum effective learning.

DayWater: an Adaptive Decision Support System for Urban Stormwater Management

The European DayWater project has developed a prototype of an Adaptive Decision Support System (ADSS) related to urban stormwater pollution source control. The DayWater ADSS greatly facilitates decision-making for stormwater source control, which is currently impeded by the large number of stakeholders involved and by the necessary multidisciplinary knowledge. This book presents the results of this project, providing new insights into both technical and management issues. The main objectives of its technical chapters are pollution source control modelling, risk and impact assessment, and evaluation and comparison of best management practices. It also covers management aspects, such as the analysis of the decision-making processes in stormwater source control, at a European scale, and stormwater management strategies in general. The combination of scientific-technical and socio-managerial knowledge, with the strong cooperation of numerous end-users, reflects the innovative character of this book which includes actual applications of the ADSS prototype in significant case studies. DayWater: an Adaptive Decision Support System for Urban Stormwater Management contains 26 chapters collectively prepared by DayWater scientific partners and end-users associated with this European Research and Development project. It includes: * A general presentation of the DayWater Adaptive Decision Support System (ADSS) structure and operation modes, * A detailed description of the major components of this ADSS prototype, * The assessment of its components in significant case studies in France, Germany and Sweden, * The proceedings of the International Conference on Decision Support Systems for Integrated Urban Water Management, held in Paris on 3-4 November 2005. The book presents the ADSS prototype including a combination of freely accessible on-line databases, guidance documents, road maps and modelling or multi-criteria analysis tools. As demonstrated in several significant case studies the challenge for stormwater managers is to make the benefits of urban stormwater management visible to society, resulting in active co-operation of a diversity of stakeholders. Only then, will sustainable management succeed. DayWater: an Adaptive Decision Support System for Urban Stormwater Management advances this cause of sustainable urban management through Urban stormwater management, and makes achievable (by means of risk and vulnerability tools which are included) the goal of integrated urban water management (IUWM).

E-learning for the careers profession: What are the lessons for the use of IT in the delivery of IAG?

The increased use of online services for Information, Advice and Guidance has been paralleled by changes in the ways in which careers practitioners access their own continuing professional development. This article offers an evaluation of e-learning and blended learning experiences, which reinforces the importance of socialisation in learning. This paper concludes that such enhancement in learning may be limited in online advice and guidance services, reducing the opportunities for challenge, motivation and broadening of aspirations in some cases.

Getting a grip: different actions and visual guidance of the thumb and finger in precision grasping

We manipulated the visual information available for grasping to examine what is visually guided when subjects get a precision grip on a common class of object (upright cylinders). In Experiment 1, objects (2 sizes) were placed at different eccentricities to vary the relative proximity to the participant's (n=6) body of their thumb and finger contact positions in the final grip orientations, with vision available throughout or only for movement programming. Thumb trajectories were straighter and less variable than finger paths, and the thumb normally made initial contact with the objects at a relatively invariant landing site, but consistent thumb first-contacts were disrupted without visual guidance. Finger deviations were more affected by the object's properties and increased when vision was unavailable after movement onset. In Experiment 2, participants (n=12) grasped 'glow-in-the-dark' objects wearing different luminous gloves in which the whole hand was visible or the thumb or the index finger was selectively occluded. Grip closure times were prolonged and thumb first-contacts disrupted when subjects could not see their thumb, whereas occluding the finger resulted in wider grips at contact because this digit remained distant from the object. Results were together consistent with visual feedback guiding the thumb in the period just prior to contacting the object, with the finger more involved in opening the grip and avoiding collision with the opposite contact surface. As people can overtly fixate only one object contact point at a time, we suggest that selecting one digit for online guidance represents an optimal strategy for initial grip placement. Other grasping tasks, in which the finger appears to be used for this purpose, are discussed.

Dorsal premotor cortex is involved in switching motor plans.

Previous studies have shown that neural activity in primate dorsal premotor cortex (PMd) can simultaneously represent multiple potential movement plans, and that activity related to these movement options is modulated by their relative subjective desirability. These findings support the hypothesis that decisions about actions are made through a competition within the same circuits that guide the actions themselves. This hypothesis further predicts that the very same cells that guide initial decisions will continue to update their activities if an animal changes its mind. For example, if a previously selected movement option suddenly becomes unavailable, the correction will be performed by the same cells that selected the initial movement, as opposed to some different group of cells responsible for online guidance. We tested this prediction by recording neural activity in the PMd of a monkey performing an instructed-delay reach selection task. In the task, two targets were simultaneously presented and their border styles indicated whether each would be worth 1, 2, or 3 juice drops. In a random subset of trials (FREE), the monkey was allowed a choice while in the remaining trials (FORCED) one of the targets disappeared at the time of the GO signal. In FORCED-LOW trials the monkey was forced to move to the less valuable target and started moving either toward the new target (Direct) or toward the target that vanished and then curved to reach the remaining one (Curved). Prior to the GO signal, PMd activity clearly reflected the monkey's subjective preference, predicting his choices in FREE trials even with equally valued options. In FORCED-LOW trials, PMd activity reflected the switch of the monkey's plan as early as 100 ms after the GO signal, well before movement onset (MO). This confirms that the activity is not related to feedback from the movement itself, and suggests that PMd continues to participate in action selection even when the animal changes its mind on-line. These findings were reproduced by a computational model suggesting that switches between action plans can be explained by the same competition process responsible for initial decisions.

How to deploy online guidance during a major incident

The experience of users of the web resource developed by the Health Protection Agency, following the arrival of H1N1 influenza, can be used to formulate criteria for web communication of up-to-date guidance in any incident management. Users participated in an online questionnaire survey. Responses were analysed quantitatively and qualitatively. Seventy-four per cent (95 per cent CI 67-81) of respondents rated the online content as ‘excellent’ or ‘good’, with higher levels of satisfaction among healthcare professionals. Across all respondent categories there was demand for information more specific to their circumstances, alongside implementation of mechanisms such as text and e-mail to alert users to updates of web content. Based on the study findings, several recommendations were made on the use of similar web-based resources in future. With consideration of these recommendations, this strategy of web-based communication can be employed in other high profile incidents requiring a national response.

Guest editor’s introduction: state-of-the-art and current developments in local tumor therapy

Over the last 20 years image-guided tumor therapy experienced a dramatic development. This development is ruled by two facts: (1) continuously improved imaging with respect to tumor detection, therapy monitoring and guidance, as well as post therapy follow-up; and (2) significant advances in the usability and efficacy of minimal-invasive therapeutical techniques and devices. Robust, high resolution and high contrast imaging by ultrasound, computed tomography and magnetic resonance tomography together with the use of contrast agents for the respective imaging modalities is the crucial component of detecting, characterizing, staging, and follow-up in most tumors. Moreover, rapid real-time imaging by ultrasound, projection radiography, CT, and even MRI allow online guidance for the placement of minimal-invasive therapy devices as well as monitoring instant local therapeutic effects. With respect to general oncological and surgical conditions, surgery is the method of choice in the therapy of most tumors. However, overall only 15–30% of patients with malignancies are suitable for a primary surgical therapy with curative intention. Therefore, modern chemotherapies including the wide use of biologicals are considered to be the main columns in adjuvant and neoadjuvant treatment regimens—taking into account that there will be no long-term curative effect in most of the cases. Based on the positive data of surgical resection in patients with limited tumor load and the resulting longterm survival, the concept of local ablative therapy—with and without concomitant chemotherapy—evolved for cases where a surgical treatment is not possible anymore due to medical and/or technical reasons. In general, four basically different ablative local

Introducing an on-line adaptive procedure for prostate image guided intensity modulate proton therapy

With on-line image guidance (IG), prostate shifts relative to the bony anatomy can be corrected by realigning the patient with respect to the treatment fields. In image guided intensity modulated proton therapy (IG-IMPT), because the proton range is more sensitive to the material it travels through, the realignment may introduce large dose variations. This effect is studied in this work and an on-line adaptive procedure is proposed to restore the planned dose to the target. A 2D anthropomorphic phantom was constructed from a real prostate patient's CT image. Two-field laterally opposing spot 3D-modulation and 24-field full arc distal edge tracking (DET) plans were generated with a prescription of 70 Gy to the planning target volume. For the simulated delivery, we considered two types of procedures: the non-adaptive procedure and the on-line adaptive procedure. In the non-adaptive procedure, only patient realignment to match the prostate location in the planning CT was performed. In the on-line adaptive procedure, on top of the patient realignment, the kinetic energy for each individual proton pencil beam was re-determined from the on-line CT image acquired after the realignment and subsequently used for delivery. Dose distributions were re-calculated for individual fractions for different plans and different delivery procedures. The results show, without adaptive, that both the 3D-modulation and the DET plans experienced delivered dose degradation by having large cold or hot spots in the prostate. The DET plan had worse dose degradation than the 3D-modulation plan. The adaptive procedure effectively restored the planned dose distribution in the DET plan, with delivered prostate D98%, D50% and D2% values less than 1% from the prescription. In the 3D-modulation plan, in certain cases the adaptive procedure was not effective to reduce the delivered dose degradation and yield similar results as the non-adaptive procedure. In conclusion, based on this 2D phantom study, by updating the proton pencil beam energy from the on-line image after realignment, this on-line adaptive procedure is necessary and effective for the DET-based IG-IMPT. Without dose re-calculation and re-optimization, it could be easily incorporated into the clinical workflow.

On-line guidance with trajectory constraints for terminal area energy management of re-entry vehicles

In this article, an on-line guidance strategy for terminal area energy management phase of a re-entry flight is proposed. In order to fulfil the objectives of this flight phase, the algorithm continuously performs long- and short-term on-line trajectory generation, also accounting for the most relevant vehicle and trajectory constraints. Long-term guidance computes a reference trajectory which minimizes the distance from the final target. Short-term guidance generates the control commands by computing a trajectory that minimizes the displacement from the reference one, thus compensating for the errors due to the environmental disturbances and to the uncertainties of the vehicle model. In the proposed guidance strategy, the main vehicle performance constraints are appropriately accounted for, thus guaranteeing adaptivity in the failure situations where the manoeuvring capabilities are reduced. The proposed guidance strategy has been developed in the framework of the unmanned space vehicle program of the Italian Aerospace Research Centre for the execution of Dropped Transonic Flight Test second mission. In this article, the algorithm performances and robustness to the vehicle initial state have been assessed through a preliminary Monte Carlo analysis. Furthermore, several simulations with bank angle and angle of attack limitations have shown the effectiveness of the algorithm in the presence of reduced manoeuvring capabilities.