Navigation Cost Research Articles

Online Aerial Terrain Mapping for Ground Robot Navigation.

This work presents a collaborative unmanned aerial and ground vehicle system which utilizes the aerial vehicle’s overhead view to inform the ground vehicle’s path planning in real time. The aerial vehicle acquires imagery which is assembled into a orthomosaic and then classified. These terrain classes are used to estimate relative navigation costs for the ground vehicle so energy-efficient paths may be generated and then executed. The two vehicles are registered in a common coordinate frame using a real-time kinematic global positioning system (RTK GPS) and all image processing is performed onboard the unmanned aerial vehicle, which minimizes the data exchanged between the vehicles. This paper describes the architecture of the system and quantifies the registration errors between the vehicles.

Design and Experimental Testing of a Free-Running Ship Motion Control Platform

In recent years, ship motion control has been used in unmanned merchant ships. It is a key issue in the sailing performance and navigation cost of unmanned vessels. The merchant ship trajectory and attitude are always generated from the response mechanism for ship motion, which uses one rudder and one propeller as the actuator. Therefore, it is a typical underactuated ship. However, there is not a specialized control test platform for unmanned merchant ships, in particular container ships. A precise merchant ship motion control platform is crucial; its computing power and motion attitude monitoring are difficult to solve by ship-borne computers. To solve this problem, a new free-running ship motion control platform is proposed, which realizes ship attitude monitoring and various motion control experiments. The proposed platform is novel as it embeds ship motion parameters and control parameters in the ship motion model, which successfully solves the precise control of the ship motion control experiment with linear or nonlinear dynamics. In this paper, the design scheme of the ship motion control platform is first presented. Then, the operating principle of the platform is shown, and the adaptive model of the ship plane motion is selected. A series of free-running model experiments and simulations is conducted to test performance of the new platform. To this end, the proposed platform can meet the requirements.

The Digital Privacy Paradox: Small Money, Small Costs, Small Talk

'Notice and Choice' has been a mainstay of policies designed to safeguard consumer privacy. This paper investigates distortions in consumer behavior when faced with notice and choice which may limit the ability of consumers to safeguard their privacy using field experiment data from the MIT digital currency experiment. There are three findings. First, the effect small incentives have on disclosure may explain the privacy paradox: Whereas people say they care about privacy, they are willing to relinquish private data quite easily when incentivized to do so. Second, small navigation costs have a tangible effect on how privacy-protective consumers' choices are, often in sharp contrast with individual stated preferences about privacy. Third, the introduction of irrelevant, but reassuring information about privacy protection makes consumers less likely to avoid surveillance, regardless of their stated preferences towards privacy.

Using a Compliant, Unactuated Tail to Manipulate Objects

We demonstrate manipulation of objects using the dynamics of a rope-like structure attached to a mobile robot as a passive tail. Three challenges arise in modeling and planning: the physics involved is nontrivial, the tail is underactuated, and motions of the object are nondeterministic. For such systems, some actions are well characterized by a simplified motion model (e.g., for dragging objects), but we resort to data-driven methods for others (e.g., striking motions). A sampling-based motion planner, adapted to deal with nondeterministic object motions, is used to optimize motion sequences based on a specified preference over a set of objectives, such as execution time, navigation cost, or collision likelihood. Experiments show that a robot with a passive tail can manipulate cylindrical objects with (quasi-static) dragging, dynamic striking motions, and combinations thereof. The method produces solutions that suit diverse preferences effectively, and we analyze the complementary nature of dynamic and quasi-static motions, showing that there exist regimes where transitions between the two are indeed desirable, as reflected in the plans produced.

Economic evaluations of patient-navigation programs in cancer care.

14 Background: Lack of coordination is challenging our health care systems. This is especially true in cancer care, which is based on multiple treatment alternatives and several types of patient-professional interactions. One recommendation is to develop patient navigation programs based on telemedicine in order to avoid costs that are due to under-coordination among providers and/or between patients and providers. The objective of our study was to identify the evidence on the economic impact of such programs in oncology, and to develop a methodological framework to conduct economic evaluations. Methods: We conducted a literature review, exploring articles indexed in Medline (2005-2015), and focusing on economic evaluations of navigation programs in oncology, with particular attention to the use of telemedicine. Results: Of the 14 studies included, nine were randomized controlled trials. Four studies adopted a societal perspective. Every study computed the direct costs of the program. Six studies included indirect costs in the total costs associated with the program, mainly based on patient productivity loss and travel cost. Only two papers included indirect costs associated with informal care. Two studies showed that patient navigation programs were less costly than standard care. Most of the total cost of patient navigation is attributable to direct medical costs (i.e. patient admission, diagnostic follow-up and medical intervention). Conclusions: More evidence is needed regarding the economic impact of navigation programs in oncology. This review provides some guidance for the design of economic evaluations. If these programs are funded through public resources, a societal perspective should be adopted since it covers the direct, indirect and intangible costs of the program. Furthermore, a key strategy will be to identify the most common situations of under-coordination occurring alongside the usual care pathway and measure avoidable costs. This advocates for an extended use of economic evaluations based on randomized controlled trials.

Abstract P6-12-08: Healthcare barrier profiles in patients navigated for cancer screening and treatment and the impact of the affordable care act

Abstract Background: The underserved community experiences barriers to cancer screening that result in overall greater mortality rates across all cancers. Insurance coverage brought forth by the Affordable Care Act has the potential to significantly impact these barriers through reducing the burden of health care cost on the patient. In this study the authors observe the impact of the Affordable Care Act on the barrier profiles presented by the patients navigated for cancer screening and treatment. Methods: Patient navigation encounters were recorded for a total of 1146 patients navigated for cancer screening and treatment at the Cleveland Clinic Foundation from the years 2012 through 2015. A total of 3259 encounters were classified into barrier types. Health care billed encounters were retrieved from EPIC for this group of patients from the time they entered patient navigation and classified in terms of insurance coverage. Patients were categorized according to their barrier profile. Appropriate generalized linear regression models were used to test for association of these profiles to number and types of navigation and health care encounters and cost, and to test for change in types of encounters and patient barrier profiles through time. Results: The insurance barrier is present in 23% of all navigation encounters. Patients presenting with an insurance barrier had a greater mean number of navigation (p<0.001) and health care encounters (p<0.006), had a greater proportion of self-paid health care encounters (p<0.001) and a lower total cost billed for health care encounters after controlling for number of encounters (p<0.001) . The access barrier is present in 53% of navigation encounters while patients that present with only the access barrier account for 42% of the entire sample. Patients that present with only the access barrier have doubled every year (OR 2.2 per year, 95% CI [1.8 2.6]) from 2012 to 2015, while the proportion of self-paid health care encounters (OR 0.26 per year, 95% CI [0.25 0.28]) and the presence of the insurance barrier (OR 0.55 per year, 95% CI [ 0.49 0.62]) have more than halved during this time period. Conclusion: Although the Affordable Care Act has clearly had an impact by lowering the number of insurance barrier navigation encounters through time, it has uncovered access as the predominant remaining barrier. Understanding and targeting the access barrier will be the most effective way to potentiate the effects of the ACA on patients being navigated for cancer screening and treatment. Citation Format: Raska P, Ott MA, Steele A, Bailey A, Hickman D, Allen D, Urbanek D, Glass K, Bailey J, Bell K, Montero A, Abraham J. Healthcare barrier profiles in patients navigated for cancer screening and treatment and the impact of the affordable care act. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-12-08.

Study on a Numerical Navigation System in the East China Sea

High winds, ocean current as well as wind-induced ocean waves can affect ship safety and navigation cost. To avoid such rough ocean states and make use of beneficial ocean current, an exact ship position considering about the weather and ocean information is of great importance. In our study, a powerful typhoon in the Kuroshio Current area of the East China Sea was studied to construct the Numerical Navigation System. Information of ocean winds, wind-induced ocean waves as well as the strong western boundary Kuroshio Current is firstly generated by modern weather and ocean models as a combination and then provided to a ship maneuvering model to construct a numerical ship navigation system. Effects of typhoon, wind-induced ocean waves as well as ocean currents on ship navigation could be found quantitatively by utilizing this method.

Analysis of 3D PPN guidance laws for nonmaneuvering target

Unlike the traditional ways adopted by most of the researchers, the rotating angle of relative velocity is adopted in this work as the independent variable to analyze the analytical solution of impact angle, capture region (with or without finite line of sight (LOS) turn rate constraint), range to go, time to go, and a defined fuel cost of a traditional pure proportional navigation (PPN) guidance law for both nonmaneuvering moving, and stationary targets.

Determinants of slow steaming and implications on service patterns

The research focuses on the impact of the shipping strategy to decrease the commercial speed of container vessels, in order to reduce the bunker costs, on current service patterns. In this regard, the study also hypothesizes potential development trends in the near future. The reduction of the commercial speed, commonly referred to as “slow steaming,” has been introduced to mitigate the negative effects of the recent economic crisis by cutting navigation costs and reducing the capacity supplied in order to assure a more efficient fleet deployment. Nowadays, this practice provokes a strong impact on maritime services and inter-port competition, as it leads to differentiate the offer of shipping services, combining fast and direct services among main hubs and cheaper and slower services also calling on small ports.The paper addresses the impact of slow steaming in the major shipping services and discusses the effects on service patterns between Asia and Europe, bringing practical insights for ocean carriers and ports.

Accelerometer-Based Navigation Is as Accurate as Optical Computer Navigation in Restoring the Joint Line and Mechanical Axis After Total Knee Arthroplasty: A Prospective Matched Study

The Zimmer iASSIST system is a novel accelerometer-based navigation system for TKA. 76 patients (76 knees) were prospectively matched for age, BMI, gender, diagnosis, and pre-operative scores, and underwent TKA using the iASSIST (n=38) or optical CAS (n=38). There were no significant differences in clinical outcomes or satisfaction rates at six months post-operatively (P>0.05). Mechanical axis was 1.8±1.3° in the iASSIST cohort versus 2.1±1.6° in the CAS cohort (P=0.543). There were no significant differences in number of outliers for mechanical axis (P=1.000), coronal femoral-component angle (P=0.693), coronal tibial-component angle (P=0.204) or joint line deviation (P=1.000). The duration of surgery was significantly longer in the CAS group (P<0.001), while the added cost of accelerometer-based navigation was approximately $1000 per operation.

Corruption and hold-up: the role of intermediaries

Corrupt contracts are illegal and, therefore, vulnerable to hold-up. That is, a bureaucrat who has accepted a bribe from a firm in exchange for a license may still choose not to grant the firm that license (hold-up). This paper develops a model to study the role that intermediaries play in preventing hold-up. There are two types of firms, good firms that are legally entitled to receive a license, and harmful firms that are not. Without intermediaries only good firms enter the market, and harmful firms do not enter because of hold-up. Intermediaries are legally permitted to help firms reduce their navigation costs of obtaining licenses. Thus, intermediaries increase entry of good firms. However, by utilizing the legal aspects of their transaction with good firms as leverage against the bureaucrat, intermediaries can prevent hold-up among harmful firms. Thus, intermediaries increase participation by both good and harmful firms and their welfare costs are ambiguous. Data obtained from occurrences of violations of the Foreign Corrupt Practices Act are broadly consistent with our model.

Methods of Calculating Ship Resistance on Limited Waterways

Abstract Nowadays predicting transportation costs is more and more important. Most significant part of inland navigation's costs are the costs of fuel. Fuel consumption is related to operating conditions of ship's propulsion system and its resistance. On inland waterways the ship resistance is strictly related to the depth of the waterway. There is a tendency to build a formula that allows its user to calculate the resistance of any inland waterway vessel, but researches claim that most of them are accurate only for particular types of ships and/or operating conditions. The paper presents selected methods of calculating ship resistance on inland waterways. These methods are examined for different types of ships and different conditions using results of model tests. The performed comparison enabled selecting the best option for pushboats and pushed barge trains, but also showed that any of the tested methods is good enough to be used for calculating the resistance of motor cargo vessels. For this reason, based on known equations and using the regression method, the authors have formulated a new method to calculate the resistance of motor cargo vessels on limited waterway. The method makes use of ship's geometry and depth of waterway in relation to ship's speed. Correlating the ship's speed with its resistance and going further with fuel consumption, enables to calculate the costs of voyage depending on the delivery time. The comparison of the methods shows that the new equation provides good accuracy in all examined speed ranges and all examined waterway depths.

Fire Hazard Safety Optimization

Abstract This article provides a study for fire hazard safety in building environments. The working hypothesis is that the navigation costs and hazard spread are deterministically modeled over time. Based on the dynamic navigation costs under fire hazard, the article introduces the notion of dynamic safety in a recursive manner. Using the recursive equations, an algorithm is proposed to calculate the dynamic safety and successor matrices.

Cost-effectiveness of patient navigation to increase adherence with screening colonoscopy among minority individuals.

Colorectal cancer (CRC) screening is underused by minority populations, and patient navigation increases adherence with screening colonoscopy. In this study, the authors estimated the cost-effectiveness of navigation for screening colonoscopy from the perspective of a payer seeking to improve population health. A validated model of CRC screening was informed with inputs from navigation studies in New York City (population: 43% African American, 49% Hispanic, 4% white, 4% other; base-case screening: 40% without navigation, 65% with navigation; navigation costs: $29 per colonoscopy completer, $21 per noncompleter, $3 per non-navigated individual). Two analyses compared: 1) navigation versus no navigation for 1-time screening colonoscopy in unscreened individuals aged ≥ 50 years; and 2) programs of colonoscopy with versus without navigation versus fecal occult blood testing (FOBT) or fecal immunochemical testing (FIT) for individuals ages 50 to 80 years. In the base case: 1) 1-time navigation gained quality-adjusted life-years (QALYs) and decreased costs; 2) longitudinal navigation cost $9800 per QALY gained versus no navigation, and, assuming comparable uptake rates, it cost $118,700 per QALY gained versus FOBT but was less effective and more costly than FIT. The results were most dependent on screening participation rates and navigation costs: 1) assuming a 5% increase in screening uptake with navigation, and a navigation cost of $150 per completer, 1-time navigation cost $26,400 per QALY gained; and 2) longitudinal navigation with 75% colonoscopy uptake cost <$25,000 per QALY gained versus FIT when FIT uptake was <50%. Probabilistic sensitivity analyses did not alter the conclusions. Navigation for screening colonoscopy appears to be cost-effective, and 1-time navigation may be cost-saving. In emerging health care models that reward outcomes, payers should consider covering the costs of navigation for screening colonoscopy.

Cost-effectiveness of navigated radiofrequency ablation for hepatocellular carcinoma in China.

Real-time virtual sonography (RVS) is a promising navigation technique for percutaneous radiofrequency ablation (RFA) treatment, especially in ablating nodules poorly visualized on conventional ultrasonography (US). However, its cost-effectiveness has not been established. The purpose of this study is to evaluate the cost-effectiveness of RVS navigated RFA (RVS-RFA) relative to US guided RFA (US-RFA) in patients with small hepatocellular carcinoma (HCC) in China, from the modified societal perspective. A state-transition Markov model was created using TreeAge Pro™ 2012. The parameters used in the model, including natural history of HCC patients, procedure efficacy and related costs, were obtained from a systematic search of literature through PubMed, EMBASE, and Science Citation Index databases. The simulated cohort was patients with solitary, small HCC (<3 cm in diameter) and Child-Pugh class A or B, whose tumors are poorly visualized in B-mode US but clearly detectable by CT or MRI. In this cohort of difficult cases, RVS-RFA was a preferred strategy saving 2,467 CNY ($392) throughout the patient's life while gaining additional 1.4 QALYs compared with conventional US guidance. The results were sensitive to the efficacy of US-RFA and RVS-RFA including complete ablation rate and local recurrence rate, the median survival for patients with progressive HCC, the probability of performing RFA for recurrent HCC, and the cost of RVS navigation, disposable needle or hospitalization. RVS-RFA is a dominant strategy for patients with small HCC unidentifiable in B-mode US, in terms of cost savings and QALYs gained, relative to the conventional US-guided method.

Optimizing adequacy of bowel cleansing for colonoscopy: recommendations from the US Multi-Society Task Force on Colorectal Cancer.

Optimizing Adequacy of Bowel Cleansing for Colonoscopy: Recommendations From the US Multi-Society Task Force on Colorectal Cancer

Behavioral Economics, Internet Search, and Antitrust

Google dominates on-line search in Europe and the United States. The search engine has faced a continuing inquiry by the European Commission for anticompetitive conduct, and the Federal Trade Commission (FTC) has recently concluded an investigation that left key questions unanswered. Drawing on behavioral economics, the Article proposes that internet search services with dominant positions can strategically select and promote co-owned services to increase consumers’ costs of switching to alternative services, i.e., Google’s placement of popular links, such as YouTube and Google Maps, on its launch page. Relying on Daniel Kahneman’s division of the control mechanisms of human action between the automatic, intuitive, and habitual (“System One”) and the effortful, deliberate, conscious (“System Two”), the Article suggests that consumers can reduce online navigation costs by placing their most frequently used services on their launch place. This effect might have greatest impact if the linked sites are frequently used internet services — like YouTube or Google books. The Article concludes by suggesting possible remedies and analyzing First Amendment concerns.

Costs and outcomes evaluation of patient navigation after abnormal cancer screening: evidence from the Patient Navigation Research Program.

Navigators can facilitate timely access to cancer services, but to the authors' knowledge there are little data available regarding their economic impact. The authors conducted a cost-consequence analysis of navigation versus usual care among 10,521 individuals with abnormal breast, cervical, colorectal, or prostate cancer screening results who enrolled in the Patient Navigation Research Program study from January 1, 2006 to March 31, 2010. Navigation costs included diagnostic evaluation, patient and staff time, materials, and overhead. Consequences or outcomes were time to diagnostic resolution and probability of resolution. Differences in costs and outcomes were evaluated using multilevel, mixed-effects regression modeling adjusting for age, race/ethnicity, language, marital status, insurance status, cancer, and site clustering. The majority of individuals were members of a minority (70.7%) and uninsured or publically insured (72.7%). Diagnostic resolution was higher for navigation versus usual care at 180 days (56.2% vs 53.8%; P = .008) and 270 days (70.0% vs 68.2%; P < .001). Although there were no differences in the average number of days to resolution between the 2 groups (110 days vs 109 days; P = .63), the probability of ever having diagnostic resolution was higher for the navigation group versus the usual-care group (84.5% vs 79.6%; P < .001). The added cost of navigation versus usual care was $275 per patient (95% confidence interval, $260-$290; P < .001). There was no significant difference in stage distribution among the 12.4% of patients in the navigation group vs 11% of the usual-care patients diagnosed with cancer. Navigation adds costs and modestly increases the probability of diagnostic resolution among patients with abnormal screening test results. Navigation is only likely to be cost-effective if improved resolution translates into an earlier cancer stage at the time of diagnosis.

An Approach to Website Structure Optimization Based on Navigation Cost

Website structure was described as an un-weighted digraph. The concept of website navigation cost as a measurement scale to evaluate the optimization degree of the website structure was presented. Based on the ideas of semantic similarity and information entropy, a quantification model of the website navigation cost was built up. And an improved Path Tree Spanning Algorithm was proposed to construct all the access paths of the website. Case study shows that the approach introduced in this paper can not only bring the new ideas and methods to the website structure optimization, but also provide further support for the website designers to develop optimization design of the website.

Customs of the River: Governing the Commons within a Nineteenth-Century Steamboat Economy

This paper uncovers a lost world indigenous to the legal history of the United States, a place where law was used as an instrument not in a way familiar to readers of Willard Hurst, as a means to identify natural resources as private property to be allocated for exploitation by the highest bidder, but instead as a means to preserve landscapes as property sustainably enjoyed by a multiplicity of actors for commercial ends. Focusing upon a single suit brought in 1854 to assign liability for a steamboat collision, where the issue became whether pilots followed the of the at a particular bend in the Ohio River, the paper relates how through the of the inquiry, Jacksonian judges in the 1830s and 1840s permitted a wild, unimproved river to speak at trial in order to keep American environments open to the disorganized public as a whole. By the 1850s, pressed by insurers seeking standardized commercial rules of the road, federal administrators promoted a more uniform, state-managed vision. To maintain the river’s status as a common highway with the customs inquiry now out of fashion, Humphrey Leavitt, the Jacksonian judge in this case, eventually developed new rules that shared the costs of navigation between private actors in a way that maintained the Ohio River as a privately-ordered space.