Dimitri Nowak

Dr. Dimitri Nowak

orcid

Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 February 2021 in Water
Verified
Journal Article
Open access
PDF file
CKChristian Kühnert
Christian Kühnert
NGNaga Mamatha Gonuguntla
Naga Mamatha Gonuguntla
HKHelene Krieg
Helene Krieg
DNDimitri Nowak
Dimitri Nowak
JTJorge A. Thomas
Jorge A. Thomas
Every morning, water suppliers need to define their pump schedules for the next 24 h for drinking water production. Plans must be designed in such a way that drinking water is always available and the amount of unused drinking water pumped into the network is reduced. Therefore, operators must accurately estimate the next day’s water consumption profile. In real-life applications with standard consumption profiles, some expert system or vector autoregressive models are used. Still, in recent years, significant improvements for time series prediction have been achieved through special deep learning algorithms called long short-term memory (LSTM) networks. This paper investigates the applicability of LSTM models for water demand prediction and optimal pump control and compares LSTMs against other methods currently used by water suppliers. It is shown that LSTMs outperform other methods since they can easily integrate additional information like the day of the week or national holidays. Furthermore, the online- and transfer-learning capabilities of the LSTMs are investigated. It is shown that LSTMs only need a couple of days of training data to achieve reasonable results. As the focus of the paper is on the real-world application of LSTMs, data from two different water distribution plants are used for benchmarking. Finally, it is shown that the LSTMs significantly outperform the system currently in operation.

5 June 2018 in Water
Verified
Journal Article
Open access
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DNDimitri Nowak
Dimitri Nowak
HKHelene Krieg
Helene Krieg
MBMichael Bortz
Michael Bortz
CGChristian Geil
Christian Geil
AKAxel Knapp
Axel Knapp
Martin BohleMartin Bohle
Martin Bohle
The design and operation of water supply systems is a multicriteria task; the energy efficiency should be minimized while, at the same time, respecting technical requirements, such as the balanced operation of available pumps. On one hand, the overall system can be improved by the use of variable speed pumps. They increase the number of operating options. On the other hand, they add more complexity to the operation problem. In this paper, we discuss the difficulties associated with speed control and propose a decision support system to overcome them.

27 June 2024 in Engineering Applications of Artificial Intelligence
Verified
Journal Article
Open access
DNDimitri Nowak
Dimitri Nowak
JWJennifer Werner
Jennifer Werner
QPQuentin Parsons
Quentin Parsons
TJtomas johnson
tomas johnson
AMAndreas Mark
Andreas Mark
FEFredrik Edelvik
Fredrik Edelvik

Verified
Journal Article
Open access
PDF file
JWJennifer Werner
Jennifer Werner
DNDimitri Nowak
Dimitri Nowak
FHFranziska Hunger
Franziska Hunger
TJtomas johnson
tomas johnson
AMAndreas Mark
Andreas Mark
FEFredrik Edelvik
Fredrik Edelvik
Wind comfort is an important factor when new buildings in existing urban areas are planned. It is common practice to use computational fluid dynamics (CFD) simulations to model wind comfort. These simulations are usually time-consuming, making it impossible to explore a high number of different design choices for a new urban development with wind simulations. Data-driven approaches based on simulations have shown great promise, and have recently been used to predict wind comfort in urban areas. These surrogate models could be used in generative design software and would enable the planner to explore a large number of options for a new design. In this paper, we propose a novel machine learning workflow (MLW) for direct wind comfort prediction. The MLW incorporates a regression and a classification U-Net, trained based on CFD simulations. Furthermore, we present an augmentation strategy focusing on generating more training data independent of the underlying wind statistics needed to calculate the wind comfort criterion. We train the models based on different sets of training data and compare the results. All trained models (regression and classification) yield an F1-score greater than 80% and can be combined with any wind rose statistic.

25 May 2018 in Journal of Heat Transfer
Verified
Journal Article
Closed access
PDF file
TATommy Andersson
Tommy Andersson
DNDimitri Nowak
Dimitri Nowak
TJTomas Johnson
Tomas Johnson
AMAndreas Mark
Andreas Mark
FEFredrik Edelvik
Fredrik Edelvik
KKKarl-Heinz Küfer
Karl-Heinz Küfer

9 April 2024 in Engineering Applications of Artificial Intelligence
Verified
Journal Article
Open access
QPQuentin Parsons
Quentin Parsons
DNDimitri Nowak
Dimitri Nowak
MBMichael Bortz
Michael Bortz
TJtomas johnson
tomas johnson
AMAndreas Mark
Andreas Mark
FEFredrik Edelvik
Fredrik Edelvik