Hardware-free collision detection and braking for securing drone propellers

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Oualid Araar ◽  
Kheireddine Benjdia ◽  
Ivan Vitanov
Keyword(s):  
Collision Detection ◽  
New Products ◽  
Prototype System ◽  
Proof Of Concept ◽  
Content Type ◽  
High Speeds ◽  
Electrically Actuated ◽  
Deep Cuts ◽  
Very High ◽  
Additional Hardware

Purpose The widespread use of drones among the general public has led to an alarming increase in accidents, some with lethal consequences. As drone blades are made from rigid materials and rotate at very high speeds, their impact with a human body can result in fatal injuries. Reliable collision detection combined with near-instantaneous braking of the drone’s rotor(s) can substantially lessen the severity of injuries sustained. The purpose of this paper is to achieve a safety solution which can be easily integrated into new products, or retrofitted into existing systems. Design/methodology/approach Through a proof of concept, this paper demonstrates the possibility of detecting a collision with a drone propeller absent any hardware modifications to the drone’s instrumentation. The solution relies on current-sensor readings, ordinarily used for monitoring the battery status of electrically actuated drones. The braking is achieved purely by reconfiguring the motor’s control strategy, without the need for additional hardware, as has been the case in previous works. Findings This paper demonstrates the possibility of detecting a collision with a drone propeller absent any hardware modifications to the drone’s instrumentation. Originality/value Compared to previous works which require installing additional hardware, the solution is purely software. This makes it very easy to integrate into existing systems or new products, at no additional cost. In experiments conducted on a prototype system, the solution was shown capable of detecting a collision and braking the motor in fewer than 20 ms. This allowed attenuating centimetre-deep cuts made to a piece of meat by an unprotected rotor to mere superficial scratches.

Islamic hedging for pilgrimage funds: case of Indonesia

2019 ◽  
Vol 11 (3) ◽  
pp. 328-341
Author(s):  
Rifki Ismal ◽  
Nurul Izzati Septiana
Keyword(s):  
Exchange Rate ◽  
The Other ◽  
Exchange Rate Risk ◽  
Content Type ◽  
Other Hand ◽  
Rate Risk ◽  
Risk Identify ◽  
Hajj Season ◽  
The Right ◽  
Very High

Purpose The demand for Saudi Arabian real (SAR) is very high in the pilgrimage (hajj) season while the authority, unfortunately, does not hedge the hajj funds. As such, the hajj funds are potentially exposed to exchange rate risk, which can impact the value of hajj funds and generate extra cost to the pilgrims. The purpose of this paper is to conduct simulations of Islamic hedging for pilgrimage funds to: mitigate and minimize exchange rate risk, identify and recommend the ideal time, amount and tenors of Islamic hedging for hajj funds, estimate cost saving by pursuing Islamic hedging and propose technical and general recommendations for the authority. Design/methodology/approach Forward transaction mechanism is adopted to compute Islamic forward between SAR and Rupiah (Indonesian currency) or IDR. Findings – based on simulations, the paper finds that: the longer the Islamic hedging tenors, the better is the result of Islamic hedging, the decreasing of IDR/USD is the right time to hedge the hajj funds and, on the other hand, the IDR/SAR appreciation is not the right time to hedge the hajj funds. Findings Based on simulations, the paper finds that: the longer the Islamic hedging tenors, the better is the result of Islamic hedging, the decreasing of IDR/USD is the right time to hedge the hajj funds and, on the other hand, the IDR/SAR appreciation is not the right time to hedge the hajj funds. Research limitations/implications The research suggests the authority to (and not to) hedge the hajj fund, depending on economic conditions and market indicators. Even though the assessment is for the Indonesian case, other countries maintaining hajj funds might also learn from this paper. Originality/value To the best of author’s knowledge, this is the first paper in Indonesia that attempts to simulate the optimal hedging of hajj funds.

scholarly journals DDNB—Doubly Decentralized Network Blockchain Architecture for Application Services

2020 ◽  
Vol 10 (15) ◽  
pp. 5212
Author(s):  
Youhwan Seol ◽  
Jaehong Ahn ◽  
Sehyun Park ◽  
Mookeun Ji ◽  
Heungseok Chae ◽  
...  
Keyword(s):  
Processing Speed ◽  
Prototype System ◽  
Proof Of Concept ◽  
Service Platform ◽  
Blockchain Technology ◽  
Platform Architecture ◽  
Application Service ◽  
Verification Process ◽  
Application Developers

Decentralization and immutability characteristics of blockchain technology has attracted numerous blockchain-based systems and applications to be proposed. However, technical shortcomings such as low transaction speed, complexity, scalability, and vulnerability to certain attacks have been identified, making it challenging to use the technology on general consumer applications and services. To address the problem, we propose a new application service platform architecture called DDNB (Doubly Decentralized Network Blockchain). DDNB divides the system into multiple layers in order to take advantage of permissioned blockchain for its processing speed and security, while allowing permissionless open use of the system to application developers. To allow any node to freely participate in application services, DDNB adopts a novel periodic node self-verification process and query chaining mechanism to authenticate newly joining nodes and validate transactions effectively and efficiently. The proposed architecture is evaluated in terms of its processing speed and security on a real proof-of-concept prototype system.

scholarly journals Targeted Allele Replacement Mutagenesis of Corynebacterium pseudotuberculosis

2011 ◽  
Vol 77 (10) ◽  
pp. 3532-3535 ◽  
Author(s):  
Caray A. Walker ◽  
Willie Donachie ◽  
David G. E. Smith ◽  
Michael C. Fontaine
Keyword(s):  
Corynebacterium Pseudotuberculosis ◽  
Sequence Length ◽  
Homologous Sequence ◽  
Proof Of Concept ◽  
Rolling Circle Replication ◽  
Content Type ◽  
Rolling Circle ◽  
Allele Replacement ◽  
Marker Free ◽  
The Relationship

ABSTRACTA two-step allele replacement mutagenesis procedure, using a conditionally replicating plasmid, was developed to allow the creation of targeted, marker-free mutations inCorynebacterium pseudotuberculosis. The relationship between homologous sequence length and recombination frequency was determined, and enhanced plasmid excision was observed due to the rolling-circle replication of the mutagenesis vector. Furthermore, an antibiotic enrichment procedure was applied to improve the recovery of mutants. Subsequently, as proof of concept, a marker-free,cp40-deficient mutant ofC. pseudotuberculosiswas constructed.

Tool workspace consideration for assembly plan generation

2021 ◽  
Vol 41 (5) ◽  
pp. 612-625
Author(s):  
Akram Bedeoui ◽  
Riadh Ben Hadj ◽  
Moncef Hammadi ◽  
Nizar Aifaoui
Keyword(s):  
Collision Detection ◽  
New Product ◽  
Production Costs ◽  
Assembly Sequence ◽  
Content Type ◽  
Plan Generation ◽  
Assembly Sequences ◽  
Dynamic Interference ◽  
Time Decrease

Purpose During the design of a new product, the generation of assembly sequences plans (ASPs) has become one of the most important problems taken into account by researchers. In fact, a good mounting order allows the time decrease of the assembly process which leads to the reduction of production costs. In this context, researchers developed several methods to generate and optimize ASP based on various criteria. Although this paper aims to improve the quality of ASP it is necessary to increase the number of criteria which must be taken into account when generating ASPs. Design/methodology/approach In this paper, an ASP generation approach, which is based on three main algorithms, is proposed. The first one generates a set of assembly sequences based on stability criteria. The obtained results are treated by the second algorithm which is based on assembly tools (ATs) workspace criterion. An illustrative example is used to explain the different steps of this proposed approach. Moreover, a comparative study is done to highlight its advantages. Findings The proposed algorithm verifies, for each assembly sequence, the minimal required workspace of used AT and eliminates the ASPs non-respecting this criterion. Finally, the remaining assembly sequences are treated by the third algorithm to reduce the AT change during the mounting operation. Originality/value The proposed approach introduces the concept of AT workspace to simulate and select ASPs that respect this criterion. The dynamic interference process allows the eventual collision detection between tool and component and avoids it. The proposed approach reduces the AT change during the mounting operations.

Dynamics and Stability of Boats With Aerodynamic Support

2013 ◽  
Vol 29 (01) ◽  
pp. 17-24
Author(s):  
Konstantin I. Matveev ◽  
Nikolai Kornev
Keyword(s):  
Ground Effect ◽  
Ground Vehicles ◽  
Marine Transportation ◽  
Technical Problems ◽  
Transient Regimes ◽  
High Speeds ◽  
Effect Theory ◽  
Stability Issues ◽  
Marine Vehicle ◽  
Very High

Aerodynamic support is beneficial for achieving very high speeds of marine transportation. Wing-in-ground vehicles, power-augmented ram platforms, and ultrafast planing multihulls are examples of marine craft with air assistance. The main technical problems in the development and application of these concepts for marine transportation are to ensure motion stability and to provide adequate seaworthiness. In this article, we illustrate applications of several mathematical models for various air supported marine vehicle concepts and discuss their specific stability issues. The aerodynamic submodels are based on nonlinear vortex-lattice methods and on the extreme ground effect theory, whereas unsteady hydrodynamics of planing surfaces are treated with added-mass strip theories. The static and dynamic stability in the vicinity of equilibrium states can be analyzed by linearized approaches. However, motions in transient regimes and unsteady environments require implementation of nonlinear and fully unsteady modeling methods.

Gliding Flight of the Dog-Faced Bat Rousettus Aegyptiacus Observed in a Wind Tunnel

1971 ◽  
Vol 55 (3) ◽  
pp. 833-845 ◽  
Author(s):  
C. J. PENNYCUICK
Keyword(s):  
Wind Tunnel ◽  
Lift Coefficient ◽  
Trailing Edge ◽  
Number Range ◽  
High Speeds ◽  
Gliding Flight ◽  
Speed Range ◽  
Simple Regression Analysis ◽  
Drag Analysis ◽  
Very High

1. A bat was trained to fly in a tilting wind tunnel. Stereoscopic photographs were taken, both by reflected and by transmitted light, and measurements of best gliding angle were made. 2. Variation of wing span and area at different speeds was much less than in birds. This is attributed to the construction of the wing, which prevents the bat from folding back the manus in flight, because this would lead to collapse of the plagiopatagium. 3. The trailing edge of the wing is normally deflected upwards in flight, at least in the distal parts. This is interpreted as providing longitudinal stability. The plagiopatagialis proprii muscles appear to act as an elevator, by deflecting the trailing edge of the plagiopatagium upwards. 4. The speed range over which the bat could glide was 5·3-11·0 m/s. Its maximum lift coefficient was 1·5, and its best glide ratio 6·8:1. The Reynolds number range, based on mean chord, was 3·26 x 104 to 6·79 x 104. 5. A simple regression analysis of the glide polar indicated a very high span efficiency factor (k) and low wing profile drag coefficient (Cdp). On the other hand, a drag analysis on the assumption that k = 1 leads to an improbably large increase in the estimated Cdp at low speeds. It is suggested that the correct interpretation probably lies between these extremes, with k ≊ 1·5; Cdp would then be about 0·02 at high speeds, rising to somewhat over 0·1 at the minimum speed. 6. It would appear that the bat is not so good as a pigeon at fast gliding, but better at low-speed manoeuvring. On most points of performance, however, the two are remarkably similar.

Flow Field on Helodeck of a Frigate: A Review

2019 ◽  
Vol 161 (A4) ◽  
Keyword(s):  
Flow Field ◽  
Numerical Solutions ◽  
Offshore Structures ◽  
High Speeds ◽  
High Turbulence ◽  
The Subject ◽  
Offshore Industry ◽  
The Military ◽  
Very High ◽  
Made In

The various functions desired from a frontline warship such as a frigate, corvette or a destroyer, coupled with the requirement of very high speeds and economic viability restricting the size, necessitates a very dense arrangement of weapons and sensors on the top deck and superstructure. Accordingly, Navies across the world have faced several problems with respect to functions for which a good aerodynamic design for these structures is essential. Major issues include smoke nuisance created due to impinging of the ship's exhaust gases on to the top deck leading to possible suction by engine intakes and high turbulence in the ship's air-wake leading to ship aircraft interface concerns. The flow field on the helodeck is extremely complex due to its geometry and interaction with the wake of the ship’s superstructure. A knowledge of this complexity is essential for ensuring safe helo operations on the helodeck. The problem of ship helicopter interaction has hogged the lime light in recent times, due to rising demand for design of warships for increased stealth, especially in the past two decades. Consequently, several researchers in countries with advanced Navies have invested considerable resources towards evolving both experimental and numerical solutions for the problem. However, given the military nature of the operations, open literature on the subject containing details of such research, which can be used as reference material for present work, are limited. Considering the complexities involved in the problem, an attempt has been made in this paper to holistically review the widely scattered and limited literature in this field. A good amount of literature on marine helo applications emerge from the offshore industry. Keeping in mind that the fields of warship design and offshore structures are dissimilar and have their peculiar problems, informed conclusions have been made in drawing lessons from available literature.

The interactive effect of insight and cuteness in driving purchase likelihood: a lay belief of creativity

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Felix Septianto ◽  
Rokhima Rostiani ◽  
Widya Paramita
Keyword(s):  
New Products ◽  
Interactive Effect ◽  
Experimental Studies ◽  
New Product ◽  
Underlying Mechanism ◽  
Content Type ◽  
Narrative Study ◽  
Managerial Implications ◽  
Purchase Likelihood

PurposeWhile new product introductions can potentially promote growth and benefit for brands, it remains unclear how marketers can develop effective communication strategies to increase the chance of success for new products. The present research investigates the role of cuteness in leveraging the effectiveness of a narrative emphasizing an insight versus an effort in this regard.Design/methodology/approachThis research presents two experimental studies. Study 1 examines the moderating role of cuteness on the likelihood of purchasing a new product featuring an insight-based (vs effort-based) narrative. Study 2 extends the findings of Study 1 using different stimuli and establishes the underlying mechanism.FindingsResults show that when a cuteness appeal is present, an insight-based (vs effort-based) narrative will lead to a higher purchase likelihood. However, these differences do not emerge when a cuteness appeal is absent (a control condition). Further, perceived brand creativeness will mediate this effect.Originality/valueThe findings of this research contribute to the literature on lay belief of creativity, cuteness, and product narrative, as well as managerial implications on how to promote new products.

Sales and operations planning for new products: a parallel process?

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gustavo Bagni ◽  
Juliana Keiko Sagawa ◽  
Moacir Godinho Filho
Keyword(s):  
Design Science ◽  
Contextual Factors ◽  
New Products ◽  
Science Research ◽  
Operations Planning ◽  
Content Type ◽  
Demand Fulfillment ◽  
Viable Solution ◽  
Additional Costs ◽  
Update Frequency

PurposeThis paper aims to detail how a Sales and Operations Planning (S&OP) process can be designed to support the planning requirements of recently introduced products.Design/methodology/approachDesign science research was conducted to propose and implement an S&OP model for demand fulfillment after the introduction of new products. The results were analyzed using the CIMO (Context, Intervention, Mechanisms and Outcomes) logic, and two sets of design propositions were formulated.FindingsAn S&OP process for new products can reduce additional costs for market fulfillment by concentrating the planning efforts on new products, aligning organizational efforts, and increasing the sales and supply chain information’s update frequency.Research limitations/implicationsThe outcomes of S&OP new products were analyzed in a single organization and are limited to the contextual factors presented.Practical implicationsThis paper describes in detail how to organize an S&OP focused on new products. By considering the contextual factors and design propositions, managers can potentially increase the success of new products introduction (NPI) in their context.Originality/valueA specific S&OP process focused on new products is a viable solution and could co-exist with a traditional S&OP process. Moreover, we identified six contextual factors that influence the outcomes of the S&OP new products.

scholarly journals Design and proof of concept of an innovative very high temperature ceramic solar absorber

2017 ◽  
Author(s):  
Cédric Leray ◽  
Alain Ferriere ◽  
Adrien Toutant ◽  
Gabriel Olalde ◽  
Jean-Yves Peroy ◽  
...  
Keyword(s):  
High Temperature ◽  
Proof Of Concept ◽  
Solar Absorber ◽  
Very High
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