Forward projection model of non-central catadioptric cameras with spherical mirrors

Robotica ◽  
2016 ◽  
Vol 35 (6) ◽  
pp. 1378-1396 ◽  
Author(s):  
Nuno Goncalves ◽  
Ana Catarina Nogueira ◽  
Andre Lages Miguel

SUMMARYNon-central catadioptric vision is widely used in robotics and vision but suffers from the lack of an explicit closed-form forward projection model (FPM) that relates a 3D point with its 2D image. The search for the reflection point where the scene ray is projected is extremely slow and unpractical for real-time applications. Almost all methods thus rely on the assumption of a central projection model, even at the cost of an exact projection.Two recent methods are able to solve this FPM, presenting a quasi-closed form FPM. However, in the special case of spherical mirrors, further enhancements can be made. We compare these two methods for the computation of the FPM and discuss both approaches in terms of practicality and performance. We also derive new expressions for the FPM on spherical mirrors (extremely useful to robotics and graphics) which speed up its computation.

2015 ◽  
Vol 6 (1) ◽  
pp. 50-57
Author(s):  
Rizqa Raaiqa Bintana ◽  
Putri Aisyiyah Rakhma Devi ◽  
Umi Laili Yuhana

The quality of the software can be measured by its return on investment. Factors which may affect the return on investment (ROI) is the tangible factors (such as the cost) dan intangible factors (such as the impact of software to the users or stakeholder). The factor of the software itself are assessed through reviewing, testing, process audit, and performance of software. This paper discusses the consideration of return on investment (ROI) assessment criteria derived from the software and its users. These criteria indicate that the approach may support a rational consideration of all relevant criteria when evaluating software, and shows examples of actual return on investment models. Conducted an analysis of the assessment criteria that affect the return on investment if these criteria have a disproportionate effort that resulted in a return on investment of a software decreased. Index Terms - Assessment criteria, Quality assurance, Return on Investment, Software product


2016 ◽  
Vol 18 (1) ◽  
Author(s):  
Roelof Baard ◽  
George Nel

Background: Although research shows that almost all listed companies have corporate websites with dedicated investor relations (IR) sections that enable companies to ‘push’ information to investors, it was argued that such an asymmetrical approach to communication is insufficient for companies wishing to exercise good IR. The purpose of this study was to test the effectiveness of the Internet to act as a mechanism to achieve more interactive communication between companies and investors.Objectives: The objectives of the study were to measure the responsiveness, timeliness and relevance of companies’ responses to e-mail requests, and to test for the determinants (size, market-to-book ratio, profitability, leverage and liquidity) thereof.Method: The mystery investor approach and a content analysis were used to study the e-mail handling performance of companies. The associations between company-specific characteristics were statistically tested.Results: It was found that the e-mail handling performance of companies in this study was poor compared with previous studies. Significant relationships between company size and responsiveness and relevance, and between market-to-book ratio and relevance were reported, as well as between the contact method used to request information and relevance and the use of social media and timeliness.Conclusion: Specific areas where companies could improve their investor communications were identified. The need for further research was discussed to explain some of the relationships found, as well as those not found, in contrast to what was expected. Future research is warranted to examine the relationship between the e-mail handling performance of companies and information asymmetry and the cost of equity of companies.


2014 ◽  
Vol 665 ◽  
pp. 643-646
Author(s):  
Ying Liu ◽  
Yan Ye ◽  
Chun Guang Li

Metalearning algorithm learns the base learning algorithm, targeted for improving the performance of the learning system. The incremental delta-bar-delta (IDBD) algorithm is such a metalearning algorithm. On the other hand, sparse algorithms are gaining popularity due to their good performance and wide applications. In this paper, we propose a sparse IDBD algorithm by taking the sparsity of the systems into account. Thenorm penalty is contained in the cost function of the standard IDBD, which is equivalent to adding a zero attractor in the iterations, thus can speed up convergence if the system of interest is indeed sparse. Simulations demonstrate that the proposed algorithm is superior to the competing algorithms in sparse system identification.


2021 ◽  
pp. 34-37
Author(s):  
В.К. Сердеров ◽  
Д.В. Сердерова

Большое значение в увеличении продуктивности картофеля имеет внедрение в производство перспективных высокоурожайных сортов и гибридов, приспособленных к местным природно-климатическим условиям возделывания, от чего зависят эффективность отрасли и себестоимость продукции. Цель работы – изучить влияние климатических условий на продуктивность и качественные показатели сортов и гибридов картофеля, а также использование ими благоприятных почвенно-климатических условий высокогорья Республики Дагестан, для размножения и внедрения в производство новых перспективных, высокоурожайных, приспособленных к условиям среды выращивания сортов картофеля с комплексом хозяйственно-ценных признаков. Объектом изучения послужили сорта картофеля раннего, среднераннего и среднего сроков созревания российской, белорусской и иностранной селекции. Полевые опыты закладывали в 2014–2017 годах на высоте 2000–2200 м, на землях горного опорного пункта «Курахский» Курахского района и на равнинной провинции (Прикаспийской низменности) на территории дачного массива «Наука» Махачкалинского района Республики Дагестан. Схема посадки – 70×30 см, повторность – четырехкратная. Технология выращивания картофеля – гребневая. При проведении полевых опытов использовали общепринятые методики. Практически все сорта картофеля, выращенные на равнинной провинции, сформировали высокий урожай в первый год и при дальнейшем размножении в результате развития вирусных болезней резко снизили свои продуктивные качества. Наиболее высокая урожайность в среднем за три года отмечена у сортов Жуковский ранний (20,8 т/га), Импала (20,5 т/га), Невский (17,8 т/га), Предгорный (16,9 т/га) и Удача (16,3 т/га). В свою очередь, горная провинция Дагестана характеризовалась благоприятными почвенно-климатическими условиями для возделывания как продовольственного картофеля, так и для организации первичного семеноводства на безвирусной основе и размножения перспективных сортов этой культуры. В среднем за годы исследований в горной провинции по урожайности выделились сорта Сильвана (37,4 т/га), Удача (37,6 т/га), Рокко (33,3 т/га), Импала (31,7 т/га), Жуковский ранний (29,0 т/га), Предгорный (27,7 т/га) и Примобелла (27,7 т/га), а также гибриды № 12.40/17 (43,1 т/га) и № 13.61/61 (38,8 т/га). The introduction of promising high-yielding varieties and hybrids adapted to the local natural and climatic conditions of cultivation is of great importance in increasing the productivity of potatoes, which determines the efficiency of the industry and the cost of production. The aim of the work is to study the influence of climatic conditions on the productivity and quality indicators of potato varieties and hybrids, as well as their use of favorable soil and climatic conditions in the highlands of the Republic of Dagestan, for breeding and introducing into production new promising, high-yielding, adapted to the growing environment of potato varieties with a complex of economically valuable characteristics. The object of the study was potato varieties of early, mid-early and medium maturation periods of Russian, Belarusian and foreign selection. Field experiments were conducted in 2014–2017 at an altitude of 2000–2200 m, on the lands of the mountain stronghold Kurakhsky of the Kukhar district and on the plain province (the Caspian lowland) on the territory of the suburban area Nauka of the Makhachkala district of the Republic of Dagestan. The landing scheme is 70×30 cm, the repeatability is four times. The technology of growing potatoes is combed. When conducting field experiments, generally accepted methods were used. Almost all potato varieties grown in the lowland province formed a high yield in the first year and, with further propagation, as a result of the development of viral diseases, sharply reduced their productive qualities. The highest yield on average for three years was observed in the varieties Zhukovskiy ranniy (20.8 t/ha), Impala (20.5 t/ha), Nevsky (17.8 t/ha), Predgornyy (16.9 t/ha) and Udacha (16.3 t/ha). In turn, the mountain province of Dagestan was characterized by favorable soil and climatic conditions for the cultivation of both food potatoes, and for the organization of primary seed production on a virus-free basis and the reproduction of promising varieties of this crop. On average, over the years of research in the mountain province, the varieties Silvana (37.4 t/ha), Udacha (37.6 t/ha), Rocco (33.3 t/ha), Impala (31.7 t/ha), Zhukovskiy ranniy (29.0 t/ha), Predgornyy (27.7 t/ha) and Primobella (27.7 t/ha), as well as hybrids No.12.40/17 (43.1 t/ha) and No.13.61/61 (38.8 t/ha) were distinguished by yield.


2021 ◽  
Vol 17 (1) ◽  
pp. 48-67
Author(s):  
Monika Singh ◽  
Ganesh P. Sahu

Almost all service organizations are now well aware about global warming and advantages of green information systems (Green IS) in order to gain social and economic profit at the cost of no harmful effect on environment. Recurrent annotations in the literature have explored that for successful Green IS adoption certain keys factors are required to be considered and followed in various organizations. This paper reviews, analyzes, and corroborates 11 key factors empirically that are accountable for successful adoption of Green IS and performance improvement achievement of banking segments with special reference to the banks positioned at Lucknow, Uttar Pradesh, India. Eleven key factors are identified via in-depth literature review and examined using UTAUT2 and T-O-E models. Analysis of Moment Structure 21.0-Structural Equation Modeling tool is used in the study for data analysis and corroboration. The study will enrich the literature review in this field; also, it will be helpful to the decision makers and practitioners in different segments for successful adoption of Green IS in organizations.


2021 ◽  
pp. 1-62
Author(s):  
Rozenn Gazan ◽  
Florent Vieux ◽  
Ségolène Mora ◽  
Sabrina Havard ◽  
Carine Dubuisson

Abstract Objective: To describe existing online 24-hour dietary recall (24hDR) tools in terms of functionalities and ability to tackle challenges encountered during national dietary surveys, such as maximizing response rates and collecting high-quality data from a representative sample of the population, while minimizing the cost and response burden. Design: A search (from 2000 to 2019) was conducted in peer-reviewed and grey literature. For each tool, information on functionalities, validation and user usability studies, and potential adaptability for integration into a new context was collected. Setting: Not country-specific Participants: General population Results: Eighteen online 24hDR tools were identified. Most were developed in Europe, for children ≥10 years old and/or for adults. Eight followed the five multiple-pass steps, but used various methodologies and features. Almost all tools (except three) validated their nutrient intake estimates, but with high heterogeneity in methodologies. User usability was not always assessed, and rarely by applying real-time methods. For researchers, eight tools developed a web platform to manage the survey and five appeared to be easily adaptable to a new context. Conclusions: Among the eighteen online 24hDR tools identified, the best candidates to be used in national dietary surveys should be those that were validated for their intake estimates, had confirmed user and researcher usability, and seemed sufficiently flexible to be adapted to new contexts. Regardless of the tool, adaptation to another context will still require time and funding, and this is probably the most challenging step.


Author(s):  
Arash Farahani ◽  
Peter Childs

Strip seals are used in gas turbine engines between two static elements or between components which do not move relative to each other, such as Nozzle Guide Vanes (NGVs). The key role of a strip seal between NGV segments is sealing between the flow through the main stream annulus and the internal air system, a further purpose is to limit the inter-segmental movements. In general the shape of the strip seal is a rectangular strip that fits into two slots in adjacent components. The minimum clearance required for static strip seals must be found by accounting for thermal expansion, misalignment, and application, to allow correct fitment of the strip seals. Any increase in leakage raises the cost due to an increase in the cooling air use, which is linked to specific fuel consumption, and it can also alter gas flow paths and performance. The narrow path within the seal assembly, especially the height has the most significant affect on leakage. The height range of the narrow path studied in this paper is 0.01–0.06 mm. The behaviour of the flow passing through the narrow path has been studied using CFD modelling and measurements in a bespoke rig. The CFD and experimental results show that normalized leakage flow increases with pressure ratio before reaching a maximum. The main aim of this paper is to provide new experimental data to verify the CFD modelling for static strip seals. The typical flow characteristics validated by CFD modelling and experiments can be used to predict the flow behaviour for future static strip seal designs.


2011 ◽  
Vol 2011 ◽  
pp. 1-19
Author(s):  
Vinod Namboodiri ◽  
Abtin Keshavarzian

Collection of rare but delay-critical messages from a group of sensor nodes is a key process in many wireless sensor network applications. This is particularly important for security-related applications like intrusion detection and fire alarm systems. An event sensed by multiple sensor nodes in the network can trigger many messages to be sent simultaneously. We present Alert, a MAC protocol for collecting event-triggered urgent messages from a group of sensor nodes with minimum latency and without requiring any cooperation or prescheduling among the senders or between senders and receiver during protocol execution. Alert is designed to handle multiple simultaneous messages from different nodes efficiently and reliably, minimizing the overall delay to collect all messages along with the delay to get the first message. Moreover, the ability of the network to handle a large number of simultaneous messages does not come at the cost of excessive delays when only a few messages need to be handled. We analyze Alert and evaluate its feasibility and performance with an implementation on commodity hardware. We further compare Alert with existing approaches through simulations and show the performance improvement possible through Alert.


Author(s):  
Файзиев Р. А. ◽  
Хаитматов У. Т. ◽  
Азаматов О. Х. ◽  
Джуманиязов Ш. Р. ◽  
Хасанова Х. Х.

The article outlines the main features of the use of the theory of indefinite bundles in the evaluation of the cost-effectiveness of investment projects.He analysis of methods for quantifying the effectiveness of the IP under uncertainty suggests that the existing methods either eliminate the uncertainty from the IP model, which is inappropriate, since uncertainty is an integral characteristic of any forecast, or are unable to formally describe, and take into account all possible varieties of types of uncertainty.Methods based on the theory of fuzzy sets refer to the methods of evaluation and decision-making under conditions of uncertainty. Their use implies the formalization of the initial parameters and performance targets of the IP in the form of a vector of interval values (fuzzy interval), the hit in each interval of which is characterized by a certain degree of uncertainty.Also, the fuzzy-interval approach has advantages in solving the problems of forming an optimal portfolio of investment projects. To solve the problem of forming an optimal IP portfolio, a large number of models for the formation of an optimal IP portfolio have been developed, differing from each other in the form of objective functions, variable properties, used by mathematical methods, and uncertainty.


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