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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

A contemporary machine learning approach to detect transportation mode - A case study of Borlänge, Sweden

Golshan, Arman January 2020 (has links)
Understanding travel behavior and identifying the mode of transportation are essential for adequate urban devising and transportation planning. Global positioning systems (GPS) tracking data is mainly used to find human mobility patterns in cities. Some travel information, such as most visited location, temporal changes, and the trip speed, can be easily extracted from GPS raw tracking data. GPS trajectories can be used as a method to indicate the mobility modes of commuters. Most previous studies have applied traditional machine learning algorithms and manually computed data features, making the model error-prone. Thus, there is a demand for developing a new model to resolve these methods' weaknesses. The primary purpose of this study is to propose a semi-supervised model to identify transportation mode by using a contemporary machine learning algorithm and GPS tracking data. The model can accept GPS trajectory with adjustable length and extracts their latent information with LSTM Autoencoder. This study adopts a deep neural network architecture with three hidden layers to map the latent information to detect transportation mode. Moreover, different case studies are performed to evaluate the proposed model's efficiency. The model results in an accuracy of 93.6%, which significantly outperforms similar studies.
192

Investigation of Machine Learning Methods for Anomaly Detection and Characterisation of Cable Shoe Pressing Processes

Härenby Deak, Elliot January 2021 (has links)
The ability to reliably connect electrical cables is important in many applications. A poor connection can become a fire hazard, so it is important that cables are always appropriately connected. This thesis investigates methods for monitoring of a machine that presses cable connectors onto cables. Using sensor data from the machine, would it be possible to create an algorithm that can automatically identify the cable and connector and thus make decisions on how a connector should be pressed for successful attachment? Furthermore, would it be possible to create an anomaly detection algorithm that is able to detect whether a connector has been incorrectly pressed by the end user? If these two questions can be addressed, the solutions would minimise the likelihood of errors, and enable detection of errors that anyway do arise. In this thesis, it is shown that the k-Nearest Neighbour (kNN) algorithm and Long Short-Term Memory (LSTM) network are both successful in classification of connectors and cables, both performing with 100% accuracy on the test set. The LSTM is the more promising alternative in terms of convergence and speed, being 28 times faster as well as requiring less memory. The distance-based methods and an autoencoder are investigated for the anomaly detection task. Data corresponding to a wide variety of possible incorrect kinds of usage of the tool were collected. The best anomaly detector detects 92% of incorrect cases of varying degrees of difficulty, a number which was higher than expected. On the tasks investigated, the performance of the neural networks are equal to or higher than the performance of the alternative methods.
193

Real-time Outlier Detection using Unbounded Data Streaming and Machine Learning

Åkerström, Emelie January 2020 (has links)
Accelerated advancements in technology, the Internet of Things, and cloud computing have spurred an emergence of unstructured data that is contributing to rapid growth in data volumes. No human can manage to keep up with monitoring and analyzing these unbounded data streams and thus predictive and analytic tools are needed. By leveraging machine learning this data can be converted into insights which are enabling datadriven decisions that can drastically accelerate innovation, improve user experience, and drive operational efficiency. The purpose of this thesis is to design and implement a system for real-time outlier detection using unbounded data streams and machine learning. Traditionally, this is accomplished by using alarm-thresholds on important system metrics. Yet, a static threshold cannot account for changes in trends and seasonality, changes in the system, or an increased system load. Thus, the intention is to leverage machine learning to instead look for deviations in the behavior of the data not caused by natural changes but by malfunctions. The use-case driving the thesis forward is real-time outlier detection in a Content Delivery Network (CDN). The input data includes Http-error messages received by clients, and contextual information like region, cache domains, and error codes, to provide tailormade predictions accounting for the trends in the data. The outlier detection system consists of a data collection pipeline leveraging the technique of stream processing, a MiniBatchKMeans clustering model that provides online clustering of incoming data according to their similar characteristics, and an LSTM AutoEncoder that accounts for temporal nature of the data and detects outlier data points in the clusters. An important finding is that an outlier is defined as an abnormal amount of outlier data points all originating from the same cluster, not a single outlier data point. Thus, the alerting system will be implementing an outlier percentage threshold. The experimental results show that an outlier is detected within one minute from a cache break-down. This triggers an alert to the system owners, containing graphs of the clustered data to narrow down the search area of the cause to enable preventive action towards the prominent incident. Further results show that within 2 minutes from fixing the cause the system will provide feedback that the actions taken were successful. Considering the real-time requirements of the CDN environment, it is concluded that the short delay for detection is indeed real-time. Proving that machine learning is indeed able to detect outliers in unbounded data streams in a real-time manner. Further analysis shows that the system is more accurate during peakhours when more data is in circulation than during none peak-hours, despite the temporal LSTM layers. Presumably, an effect from the model needing to train on more data to better account for seasonality and trends. Future work necessary to put the outlier detection system in production thus includes more training to improve accuracy and correctness. Furthermore, one could consider implementing necessary functionality for a production environment and possibly adding enhancing features that can automatically avert incidents detected and handle the causes of them.
194

Återskapa mänskligt beteende med artificiell intelligens i 2D top-down wave shooter spel / Recreate human behaviour with artificial intelligence in 2D top-down wave shooter game

Bjärehall, Johannes, Hallberg, Johan January 2020 (has links)
Arbetet undersöker mänskligt beteende hos beteendeträd och LSTM nätverk. Ett spel skapades som testades av personer i en undersökning där deltagarna fick spela tillsammans med vardera agent i slumpmässig ordning för att bedöma agenternas beteende. Resultatet från undersökningen visade att beteendeträdet var den mänskliga varianten enligt deltagarna oavsett ordning som testpersonerna spelade med vardera agent. Problemet med resultatet beror antagligen till störst del på att det inte fanns tillräckligt med tid och bristande CPU kraft för att utveckla LSTM agenten ytterligare. För att förbättra och arbeta vidare med arbetet kan mer tid läggas på att träna LSTM nätverket och finjustera beteendeträdet. För att förbättra testet borde riktig multiplayer funktionalitet implementeras som gör att det går att testa agenterna jämfört med riktiga mänskliga spelare.
195

Short-Term Forecasting of Taxi Demand using a two Channelled Convolutional LSTM network / Korttidsprognos av taxiefterfrågan med ett tvåkanaligt faltningsLSTM-nätverk

Silfver, Anton January 2019 (has links)
In this thesis a model capable of predicting taxidemand with high accuracy across five different real world single company datasets is presented. The model uses historical drop off and arrival information to make accurate shortterm predictions about future taxi demand. The model is compared to and outperforms both LSTM and statistical baselines. This thesis uniquely uses a different tessellation strategy which makes the results directly applicable to smaller taxi companies. This paper shows that accurate short term predictions of taxi demand can be made using real world data available to taxi companies. MSE is also shown to be a more robust to uneven demand distributions across cities than MAE. Adding drop offs to the input had provided only marginal improvements in the performance of the model.
196

Evaluation of Neural Networks for Predictive Maintenance : A Volvo Penta Study / Utvärdering av Neuronnät för Prediktivt Underhåll : En Volvo Penta-studie

Nordberg, Andreas January 2021 (has links)
As part of Volvo Penta's initiative to further the development of predictive maintenance in their field test environments, this thesis compares neural networks in an effort to predict the occurrence of three common diagnostics trouble codes using field test data. To quantify the neural networks' performances for comparison a number of evaluation metrics were used. By training a multitude of differently configured feedforward neural networks with the processed field test data and evaluating the resulting models, it was found that the resulting models perform better than that of a baseline classifier. As such it is possible to use Volvo Penta's field test data along with neural networks to achieve predictive maintenance. It was also found that Long Short-Term Memory (LSTM) networks with methodically selected hyperparameters were able to predict the diagnostic trouble codes with the greatest performance among all the tested neural networks.
197

Comparative Analysis of Machine Learning and Sequential Deep learning Models in Higher Education Fundraising

Umeki, Atsuko 09 May 2022 (has links)
Deep learning models have been used widely in various areas and applications of our everyday lives. They could also change the way non-profit organizations work and help optimize fundraising results. In this thesis, sequential models are applied in fundraising to compare their performance against the traditional machine learning model. Sequential model is a type of neural network that is specialized for processing sequential data. Although some research utilizing machine learning algorithms in fundraising context exists, it is based on the data extracted from the specific time window, which does not take time-dependency of features into account; therefore, time-series features are independent at each data point relative to others. This approach results in loss of time notion. In this thesis, we experiment with the application of time-dependent sequential models including Long Short Term Memory (LSTM), Gated Recurrent Unit (GRU) and their variants in the fundraising domain to predict the alumni monetary contribution to the university. We also expand our study by including the architecture that treats time-invariant demographic data as a condition to the sequential layers. In this model, the time-dependent data is concatenated after running the sequential model. Sequential deep learning is empirically evaluated and compared against the traditional machine learning models. The results demonstrate the potential use of both traditional machine learning and sequential deep learning in the prediction of fundraising outcomes and offer non-profit organizations solutions to achieve their mission. / Graduate
198

Machine Learning Evaluation of Natural Language to Computational Thinking : On the possibilities of coding without syntax

Björkman, Desireé January 2020 (has links)
Voice commands are used in today's society to offer services like putting events into a calendar, tell you about the weather and to control the lights at home. This project tries to extend the possibilities of voice commands by improving an earlier proof of concept system that interprets intention given in natural language to program code. This improvement was made by mixing linguistic methods and neural networks to increase accuracy and flexibility of the interpretation of input. A user testing phase was made to conclude if the improvement would attract users to the interface. The results showed possibilities of educational purposes for computational thinking and the issues to overcome to become a general programming tool.
199

Uniform interval normalization : Data representation of sparse and noisy data sets for machine learning

Sävhammar, Simon January 2020 (has links)
The uniform interval normalization technique is proposed as an approach to handle sparse data and to handle noise in the data. The technique is evaluated transforming and normalizing the MoodMapper and Safebase data sets, the predictive capabilities are compared by forecasting the data set with aLSTM model. The results are compared to both the commonly used MinMax normalization technique and MinMax normalization with a time2vec layer. It was found the uniform interval normalization performed better on the sparse MoodMapper data set, and the denser Safebase data set. Future works consist of studying the performance of uniform interval normalization on other data sets and with other machine learning models.
200

A COMPARATIVE STUDY OF DEEP-LEARNING APPROACHES FOR ACTIVITY RECOGNITION USING SENSOR DATA IN SMART OFFICE ENVIRONMENTS

Johansson, Alexander, Sandberg, Oscar January 2018 (has links)
Syftet med studien är att jämföra tre deep learning nätverk med varandra för att ta reda på vilket nätverk som kan producera den högsta uppmätta noggrannheten. Noggrannheten mäts genom att nätverken försöker förutspå antalet personer som vistas i rummet där observation äger rum. Utöver att jämföra de tre djupinlärningsnätverk med varandra, kommer vi även att jämföra dem med en traditionell metoder inom maskininlärning - i syfte för att ta reda på ifall djupinlärningsnätverken presterar bättre än vad traditionella metoder gör. I studien används design and creation. Design and creation är en forskningsmetodologi som lägger stor fokus på att utveckla en IT produkt och använda produkten som dess bidrag till ny kunskap. Metodologin har fem olika faser, vi valde att göra en iterativ process mellan utveckling- och utvärderingfaserna. Observation är den datagenereringsmetod som används i studien för att samla in data. Datagenereringen pågick under tre veckor och under tiden hann 31287 rader data registreras i vår databas. Ett av våra nätverk fick vi en noggrannhet på 78.2%, de andra två nätverken fick en noggrannhet på 45.6% respektive 40.3%. För våra traditionella metoder använde vi ett beslutsträd med två olika formler, de producerade en noggrannhet på 61.3% respektive 57.2%. Resultatet av denna studie visar på att utav de tre djupinlärningsnätverken kan endast en av djupinlärningsnätverken producera en högre noggrannhet än de traditionella maskininlärningsmetoderna. Detta resultatet betyder nödvändigtvis inte att djupinlärningsnätverk i allmänhet kan producera en högre noggrannhet än traditionella maskininlärningsmetoder. Ytterligare arbete som kan göras är följande: ytterligare experiment med datasetet och hyperparameter av djupinlärningsnätverken, samla in mer data och korrekt validera denna data och jämföra fler djupinlärningsnätverk och maskininlärningsmetoder. / The purpose of the study is to compare three deep learning networks with each other to evaluate which network can produce the highest prediction accuracy. Accuracy is measured as the networks try to predict the number of people in the room where observation takes place. In addition to comparing the three deep learning networks with each other, we also compare the networks with a traditional machine learning approach - in order to find out if deep learning methods perform better than traditional methods do. This study uses design and creation. Design and creation is a methodology that places great emphasis on developing an IT product and uses the product as its contribution to new knowledge. The methodology has five different phases; we choose to make an iterative process between the development and evaluation phases. Observation is the data generation method used to collect data. Data generation lasted for three weeks, resulting in 31287 rows of data recorded in our database. One of our deep learning networks produced an accuracy of 78.2% meanwhile, the two other approaches produced an accuracy of 45.6% and 40.3% respectively. For our traditional method decision trees were used, we used two different formulas and they produced an accuracy of 61.3% and 57.2% respectively. The result of this thesis shows that out of the three deep learning networks included in this study, only one deep learning network is able to produce a higher predictive accuracy than the traditional ML approaches. This result does not necessarily mean that deep learning approaches in general, are able to produce a higher predictive accuracy than traditional machine learning approaches. Further work that can be made is the following: further experimentation with the dataset and hyperparameters, gather more data and properly validate this data and compare more and other deep learning and machine learning approaches.

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