969 research outputs found
Efficient Bang-Bang Model Predictive Control for Quadcopters
No full textTime-optimal model predictive control is important for achieving fast racing drones but is computationally intensive and thereby rarely used onboard small quadcopters with limited computational resources. In this work, we simplify the optimal control problem (OCP) of the position loop for several maneuvers by exploiting the fact that the solution resembles a so-called ‘bang-bang’ in the critical direction, where only the switching time needs to be found. The noncritical direction uses a ‘minimum effort’ approach. The control parameters are obtained through bisection search schemes on an analytical path prediction model. The approach is compared with a classical PID controller and theoretical time-optimal trajectories in simulations. We explain the effects of the OCP simplifications and introduce a method of mitigating one of these effects. Finally, we have implemented the ‘bang-bang’ controller as a model predictive controller (MPC) onboard a Parrot Bebop and performed indoor flights to compare the controller’s performance to a PID controller. We show that the light novel controller outperforms the PID controller in waypoint-to-waypoint flight while requiring only minimal knowledge of the quadcopter’s dynamics.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Control & Simulatio
Marketing Communications Plan for a Fintech company. Case: Rundit Oy
No full textThe objective of this thesis was to analyze the operations and strategies of fundraising in the financial aspect. How companies communicate with their investors, how a Fintech company can help and enhance the connection between them.From there, the thesis will propose the marketing communications strategy that might im-prove the number of userbase, attract more companies and investors to join the platform, and further increase customer awareness. The conclusion includes the analysis of the com-pany’s current situation, the company's strengths, and its core values, identify the goal, vision, and strategic plan. More precisely, the author sought for the correct core values of the company to improve the effectiveness of online marketing communications.The thesis is commissioned by Rundit Oy, a Finnish Fintech startup. They provide a platform that can improve communication between investors and companies. Their aim is to create a platform where the investors can have a better overview and situation of the companies that they have invested in by standardizing the process of the financial report, metrics, charts, and forecasts, etc. Furthermore, they also help the company to promote themselves, to be able to open the fundraising, to connect them with potential investors, and provide them a professional tool for investor reporting.The author uses the qualitative research method that focuses on Participator observation method and conducts a series of Semi-structured interviews to gather data. The interview involved the CEO, Product owner, and lead designer of Rundit. After gathering the necessary data, the author will draw the Business Model Canvas to identify the current value of the company, then use different analyses such as SWOT and PESTEL to support making the mar-keting communications plan
Second-order analysis and numerical approximation for bang-bang bilinear control problems
No full textWe consider bilinear optimal control problems whose objective functionals do not depend on the controls. Hence, bang-bang solutions will appear. We investigate sufficient secondorder conditions for bang-bang controls, which guarantee local quadratic growth of the objective functional in L1 . In addition, we prove that for controls that are not bang-bang, no such growth can be expected. Finally, we study the finite-element discretization and prove error estimates of bang-bang controls in L1 -norms.The first author was partially supported by the Spanish Ministerio de Economía Industria y Competitividad under research projects MTM2014-57531-P and MTM2017-83185-P. The second author was partially supported by DFG under grant Wa 3626/1-1
A 33-ppm/°C 240-nW 40-nm CMOS Wakeup Timer Based on a Bang-Bang Digital-Intensive Frequency-Locked-Loop for IoT Applications
No full textThis paper presents a wakeup timer in 40-nm CMOS for Internet-of-Things (IoT) applications based on a bang-bang Digital-intensive Frequency-Locked Loop (DFLL). A self-biased Σ Δ Digitally Controlled Oscillator (DCO) is locked to an RC time constant via a feedback loop consisting of a single-bit chopped comparator and a digital loop filter, thus maximizing the use of digital circuits while keeping only the RC network and the comparator as the sole analog blocks. Analysis and behavior level simulations of the DFLL have been carried out to guide the optimization of the long-term stability and frequency accuracy of the timer. High frequency accuracy and a 10× enhancement of long-term stability is achieved by the adoption of chopping to reduce the effect of comparator offset and 1/f noise and by the use of Σ Δ modulation to improve the DCO resolution. Such highly digitized architecture fully exploits the advantages of advanced CMOS processes, thus enabling operation down to 0.7 V and a small area (0.07 mm2). The proposed timer achieves the excellent energy efficiency (0.57 pJ/cycle at 417 kHz at 0.8-V supply) over prior art while keeping excellent on-par long-term stability (Allan deviation floor < 20 ppm) and temperature stability (33 ppm°Cat 0.8-V supply).Accepted Author Manuscript(OLD)Applied Quantum Architecture
Sufficient second-order conditions for bang-bang control problems
No full textWe provide sufficient optimality conditions for optimal control problems with bang-bang controls. Building on a structural assumption on the adjoint state, we additionally need a weak second-order condition. This second-order condition is formulated with functions from an extended critical cone, and it is equivalent to a formulation posed on measures supported on the set where the adjoint state vanishes. If our sufficient optimality condition is satisfied, we obtain a local quadratic growth condition in L1(Ω)The first author was partially supported by the Spanish Ministerio de Economía y Competitividad under project MTM2014-57531-P. The second author was partially supported by the DFG under grant Wa 3626/1-1
A 0.7-V 0.43-pJ/cycle Wakeup Timer based on a Bang-bang Digital-Intensive frequency-Locked-Loop for IoT Applications
No full textA 40-nm CMOS wakeup timer employing a bang-bang digital-intensive frequency-locked loop for Internet-of-Things applications is presented. A self-biased ΣΔ digitally controlled oscillator (DCO) is locked to an RC time constant via a single-bit chopped comparator and a digital loop filter. Such highly digitized architecture fully exploits the advantages of advanced CMOS processes, thus enabling operation down to 0.7 V and a small area (0.07 mm 2 ). Most circuitry operates at 32× lower frequency than the DCO in order to reduce the total power consumption down to 181 nW. High frequency accuracy and a 10× enhancement of long-term stability is achieved by the adoption of chopping to reduce the effect of comparator offset and 1/f noise and by the use of ΣΔ modulation to improve the DCO resolution. The proposed timer achieves the best energy efficiency (0.43 pJ/cycle at 417 kHz) over prior art while keeping excellent on-par long-term stability (Allan deviation floor <;20 ppm) and temperature stability (106 ppm/°C).Accepted Author Manuscript(OLD)Applied Quantum Architecture
Analytical Solution for Low-Thrust Transfer Orbits using Bang-Bang Control without Gravity Losses
No full textThis thesis research has focused on developing an analytical solution for low-thrust transfer orbits. Low-thrust propulsion is an attractive option for space manoeuvres and transfers, since it provides a large specific impulse and hence efficient use of propellant. Thus, the propellant mass can be decreased, which brings advantages such as higher payload mass and extended mission life.Two constraints have been posed on the thrust acceleration, which often appear as a result of optimal solutions. Firstly, only bang-bang control is allowed, thus the rocket engine can only be turned on or off. Secondly, no radial thrust is allowed, such that no gravity losses occur. The modified equinoctial elements have been chosen to describe the trajectory. If it is assumed that the eccentricity is equal to zero, analytical solutions have been derived. While this seems as a substantial restriction on the developed method, it is shown that the analytical solution provides very reasonable results for eccentricities smaller than 0.2. Furthermore, separate analytical expressions have been developed when no in-plane thrust acts on the spacecraft. For the implementation of the bang-bang control, each individual revolution around the central body is allowed to have two thrust arcs and two coasts arcs, where the analytical solutions have been used to describe the motion of the spacecraft during the thrust arcs. By cleverly choosing the switching points where the rocket engine is turned on and off, the transfer orbit is achieved in an efficient way. The performance of the developed algorithm has been assessed for different input parameters. More specifically, different magnitudes of thrust accelerations have been analyzed. Furthermore, the lengths of the thrust and coast arcs, together with the direction of the thrust force, have been varied to evaluate the applicability of the algorithm. Lastly, the algorithm has been tested with the introduction of a stop criterion, which determines the required propellant and time of flight to arrive at a set target element. The algorithm has proved to give results with relatively good accuracy for orbits with an eccentricity smaller than 0.2. However, if the time of flight or the thrust acceleration become too high, less feasible solutions are perceived.Aerospace Engineerin
Towards Soft Social Sustainability in a Hybrid Organisational Culture : case: Aava & Bang
No full textAsiantuntijatyö on suuressa murroksessa ja COVID-19-pandemia on vauhdittanut muutosta valtavasti. Pandemian aiheuttama etätyöpakko sai organisaatiot pohtimaan toimisto- ja etätyön yhdistelmän entistä suurempaa hyödyntämistä, eli hybridityömallien rakentamista osaksi toimivaa työn tekemisen mallia. Jotta hybridityö tuottaisi yritykselle parhaan mahdollisen lopputuloksen, tarvitaan muutosta myös organisaatiokulttuuriin, jotta työntekijöiden hyvinvointi säilyy ja ideaalitilanteessa myös kasvaa.
Opinnäytetyön avulla pyrittiin löytämään toimeksiantajana toimineelle mainostoimisto Aava & Bangille työkaluja, jotka tukisivat hybridiorganisaatiokulttuurin kehittämistä pehmeän sosiaalisen kestävyyden näkökulmasta. Opinnäytetyössä keskityttiin sosiaaliseen kestävyyteen, sillä se on vähiten tutkittu vastuullisuuden osa-alue, mutta sillä on mittavia vaikutuksia yrityksen henkilöstön hyvinvointiin ja sitä kautta yrityksen tuottavuuteen. Tutkimuksessa kartoitettiin yrityksen tämänhetkinen tilanne liittyen hybridityöhön, hybridiorganisaatiokulttuuriin sosiaalisen kestävyyden näkökulmasta, sekä etsittiin uusia tapoja ylläpitää ja kehittää sosiaalisesti kestävää hybridiorganisaatiokulttuuria.
Opinnäytetyö toteutettiin monimetodisena tutkimuksena, jossa aineistoa kerättiin sekä kvalitatiivisin, että kvantitatiivisin metodein. Koska aiheesta on vielä vähän tutkimustietoa, haastateltiin aiheeseen perehtynyttä asiantuntijaa syvemmän ymmärryksen saamiseksi. Tutkimukseen haastateltiin myös Aava & Bangin johtoryhmän jäsentä, jotta yrityksen sen hetkinen tilanne saatiin kartoitettua syvemmin. Tämän lisäksi toimeksiantajan henkilöstö osallistui pääosin kvantitatiiviseen kyselyyn, muutamalla kvalitatiivisella kysymyksellä, jossa kartoitettiin heidän mielipiteitä, kokemuksia ja tunteita hybridityöstä.
Tutkimuksen tulosten perusteella hybridityö jaettiin neljään osa-alueeseen; fyysiseen, digitaaliseen, sosiaaliseen, sekä henkiseen työympäristöön. Keskeisiä asioita olivat työtehtävien sijainnin optimointi, ergonomian parantaminen, laadukkaiden teknologisten ratkaisujen tarve, kyberturvallisuus, halu läpinäkyviin ja ymmärrettäviin sopimuksiin ja sääntöihin, yhteisöllisyys sekä fyysisen ja henkisen hyvinvoinnin kehittäminen. Kaiken kaikkiaan tulokset osoittivat, että pehmeä sosiaalinen kestävyys on tärkeä asia, joka on otettava huomioon optimoitaessa organisaatiokulttuuria "uuteen normaaliin".White collar work environments have seen a major transformation in recent years, accelerated in no small part by the COVID-19 pandemic. The need to work remotely as a result of social distancing restrictions has led organisations to consider how to optimise the resulting combination of office and remote work environments. The result has been the emergence of hybrid work models as part of an organisation’s normal functioning. For hybrid work to produce the best possible results for an organisation, changes to its organisational culture are required to at least maintain, if not increase, employees’ wellbeing.
The objective in this thesis was to identify tools which would support development of a hybrid organi- sational culture from the perspective of soft social sustainability. The case selected for detailed study was Aava & Bang, a Jyväskylä-based advertising agency. The principal focus in the thesis was social sustainability as it is the least studied area of sustainability but has a major impact on the wellbeing of a company's employees and on productivity and competitiveness. The study mapped Aava & Bang’s current situation regarding hybrid work, the culture of hybrid organisation from the perspective of social sustainability and searched for new ways to maintain and develop a socially sustainable hybrid organisational culture.
A mixed-method research study was carried out, in which data were collected using both qualitative and quantitative methods. Given the limited amount of prior research on the topic, a recognised hybrid work expert was first interviewed to gain a deeper understanding of pertinent issues. Next, a member of Aava & Bang's management team was interviewed to chart the company's current situation in more depth. Finally, Aava & Bang’s staff responded to a survey informed by both the interviews and the theoretical background developed by the author that mapped employees’ opinions, experiences, and feelings about hybrid work.
The results of the study, analysed within a physical, digital, social, and mental workplace framework, revealed a host of viewpoints, knowledge, experiences, and suggestions regarding hybrid work. Key issues included task-work location optimisation, improved ergonomics, the need for high-quality technological solutions, cyber security, a desire for transparent and understandable agreements & rules, a sense of community, and development of physical and mental wellbeing. Overall, results showed that soft social sustainability is an important issue to consider when optimising organisational culture for the “new normal”
Cosmology Without Bang
No full text"Cosmology Without Bang" proposes a radical rethinking of cosmic origin — not as an explosion, but as a permission. Challenging the dominant narrative of the Big Bang, this work suggests that the universe did not erupt into being through force, law, or causality, but arose through what the author calls the Primal Hazard — a metaphysical trembling that precedes structure, time, and even becoming itself. This is not a cosmology of force, but of allowance. From this original non-event — a tremble without why — emerge breath, curvature, memory, and asymmetry, which together unfold into the lived structure of reality. The universe is not the product of a singularity, but the consequence of permission. Rather than deny science, this work seeks to deepen it, suggesting that even our most elegant physical models presuppose conditions they cannot explain. Through a lyrical and philosophical style, Cosmology Without Bang invites readers to imagine a universe not founded on noise, but on nuance — not begun in command, but in a tremble that let all things be. The origin, here, is not forceful. It is gentle. Not a bang. A breath
Cosmology Without Bang
No full text"Cosmology Without Bang" proposes a radical rethinking of cosmic origin — not as an explosion, but as a permission. Challenging the dominant narrative of the Big Bang, this work suggests that the universe did not erupt into being through force, law, or causality, but arose through what the author calls the Primal Hazard — a metaphysical trembling that precedes structure, time, and even becoming itself. This is not a cosmology of force, but of allowance. From this original non-event — a tremble without why — emerge breath, curvature, memory, and asymmetry, which together unfold into the lived structure of reality. The universe is not the product of a singularity, but the consequence of permission. Rather than deny science, this work seeks to deepen it, suggesting that even our most elegant physical models presuppose conditions they cannot explain. Through a lyrical and philosophical style, Cosmology Without Bang invites readers to imagine a universe not founded on noise, but on nuance — not begun in command, but in a tremble that let all things be. The origin, here, is not forceful. It is gentle. Not a bang. A breath
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