Olee Hoi Ying Lam

Ms. Olee Hoi Ying Lam

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

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

Representative Publications

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4 August 2020 in European Journal of Remote Sensing
Verified
Journal Article
Open access
OLOlee Hoi Ying Lam
Olee Hoi Ying Lam
MDMarcel Dogotari
Marcel Dogotari
MPMoritz Prüm
Moritz Prüm
HVHemang Narendra Vithlani
Hemang Narendra Vithlani
CRCorinna Roers
Corinna Roers
RBRolf Becker
Rolf Becker
Weed control is one of the biggest challenges in organic farms or nature reserve areas where mass spraying is prohibited. Recent advancements in remote sensing and airborne technologies provide a fast and efficient means to support environmental monitoring and management, allowing early detection of invasive species. However, in order to perform weed classification, current studies mostly relied on object-based image analysis (OBIA) and proprietary software which required substantial human inputs. This paper proposes an open-source workflow for automated weed mapping using a commercially available unmanned aerial vehicle (UAV). The UAV was flown at a low altitude between 10 m and 20 m, and collected true-colour RGB imagery over a weed-infested nature reserve. The aim of this study is to develop a repeatable and robust system for early weed detection, with minimum human intervention, for classification of Rumex obtusifolius (R. obtusifolius). Preliminary results of the proposed workflow achieved an overall accuracy of 92.1% with an F1 score of 78.7%. The approach also demonstrated the capability to map R. obtusifolius in datasets collected at various flight altitudes, camera settings and light conditions. This shows the potential to perform semi- or fully automated early weed detection system in grasslands using UAV-imagery.

8 May 2024 in Ecology and Evolution
Verified
Journal Article
Open access
OLOlee Hoi Ying Lam
Olee Hoi Ying Lam
JKJens Kattge
Jens Kattge
STSusanne Tautenhahn
Susanne Tautenhahn
GBGerhard Boenisch
Gerhard Boenisch
Kyle R KovachKyle R Kovach
Kyle R Kovach
PTPhilip Townsend
Philip Townsend
Plant trait data are used to quantify how plants respond to environmental factors and can act as indicators of ecosystem function. Measured trait values are influenced by genetics, trade‐offs, competition, environmental conditions, and phenology. These interacting effects on traits are poorly characterized across taxa, and for many traits, measurement protocols are not standardized. As a result, ancillary information about growth and measurement conditions can be highly variable, requiring a flexible data structure. In 2007, the TRY initiative was founded as an integrated database of plant trait data, including ancillary attributes relevant to understanding and interpreting the trait values. The TRY database now integrates around 700 original and collective datasets and has become a central resource of plant trait data. These data are provided in a generic long‐table format, where a unique identifier links different trait records and ancillary data measured on the same entity. Due to the high number of trait records, plant taxa, and types of traits and ancillary data released from the TRY database, data preprocessing is necessary but not straightforward. Here, we present the ‘rtry’ R package, specifically designed to support plant trait data exploration and filtering. By integrating a subset of existing R functions essential for preprocessing, ‘rtry’ avoids the need for users to navigate the extensive R ecosystem and provides the functions under a consistent syntax. ‘rtry’ is therefore easy to use even for beginners in R. Notably, ‘rtry’ does not support data retrieval or analysis; rather, it focuses on the preprocessing tasks to optimize data quality. While ‘rtry’ primarily targets TRY data, its utility extends to data from other sources, such as the National Ecological Observatory Network (NEON). The ‘rtry’ package is available on the Comprehensive R Archive Network (CRAN; https://cran.r‐project.org/package=rtry) and the GitHub Wiki (https://github.com/MPI‐BGC‐Functional‐Biogeography/rtry/wiki) along with comprehensive documentation and vignettes describing detailed data preprocessing workflows.

1 May 2016
Verified
Conference Paper
Closed access
OLOlee Hoi Ying Lam
Olee Hoi Ying Lam
RKReinhard Kulke
Reinhard Kulke
MHManfred Hagelen
Manfred Hagelen
GMGregor Mollenbeck
Gregor Mollenbeck
Moving targets induce unique micro-Doppler signatures. After conducting several measurements with human, vehicle, UAV and animal as targets using a 24 GHz radar, the micro-Doppler signatures are observed through time-velocity diagrams. A simple set of micro-Doppler features are then selected and extracted from the measurement data. Results show the potential of radar as a ground surveillance applications, which can operate under wide range of weather and lighting conditions with high privacy standards and low false alarm rate. This paper also indicates that with I/Q modulation in radar, the direction of the target's motion can be preserved, thus provides a more detailed description of the measured moving target.

17 January 2022
Verified
Dataset
Open access
OLOlee Hoi Ying Lam
Olee Hoi Ying Lam
STSusanne Tautenhahn
Susanne Tautenhahn
GWGabriel Walther
Gabriel Walther
GBGerhard Boenisch
Gerhard Boenisch
PBPramod Baddam
Pramod Baddam
JKJens Kattge
Jens Kattge

23 December 2019 in Proceedings
Verified
Conference Paper
Open access
PDF file
OLOlee Hoi Ying Lam
Olee Hoi Ying Lam
BMBethany Melville
Bethany Melville
MDMarcel Dogotari
Marcel Dogotari
MPMoritz Prüm
Moritz Prüm
HVHemang Narendra Vithlani
Hemang Narendra Vithlani
FZFrank Zimmer
Frank Zimmer
Rumex obtusifolius (R. obtusifolius) is one of the most common non-cultivated.

24 December 2019 in Proceedings
Verified
Conference Paper
Open access
PDF file
HVHemang Narendra Vithlani
Hemang Narendra Vithlani
MDMarcel Dogotari
Marcel Dogotari
BMBethany Melville
Bethany Melville
MPMoritz Prüm
Moritz Prüm
OLOlee Hoi Ying Lam
Olee Hoi Ying Lam
FZFrank Zimmer
Frank Zimmer
The acquisition, storage, and processing of huge amounts of data and their fast analysis to generate information is not a new approach, but it becomes challenging through smart decision-making on the choice of hardware and software improvements. In the specific cases of environment protection, nature conservation, and precision farming, where fast and accurate reactions are required, drone technologies with imaging sensors are of interest in many research groups. However, post-processing of the images acquired by drone-based sensors such as the generation of orthomosaics from aerial images and superimposing the orthomosaics on a global map to identify the exact locations of the interested area is computationally intensive and sometimes takes hours or even days to achieve desired results. Initial tests have shown that photogrammetry software takes less time to generate an orthomosaic by running them on a workstation with higher CPU, RAM and GPU configurations. Tasks like setting up the application environment with dependencies, making this setup portable and manage installed services can be challenging, especially for small-and-medium-sized enterprises that have limited resources in exploring different architectures. To enhance the competitiveness of the small and medium-sized enterprises and research institutions, the accessibility of the proposed solution includes the integration of open-source tools and frameworks such as Kubernetes (version v1.13.4, available online: https://kubernetes.io/) and OpenDroneMap (version 0.3, available online: https://github.com/OpenDroneMap/ODM) enabling a reference architecture that is as vendor-neutral as possible. Current work is based on an on-premise cluster computing approach for fast and efficient photogrammetry process using open source software such as OpenDroneMap combined with light-weight containerization techniques such as Docker (version 17.12.1, available online: https://www.docker.io/), orchestrated by Kubernetes. The services provided by OpenDroneMap enable microservice-based architecture. These container-based services can be administered easily by a container orchestrator like Kubernetes. After setting up the servers with core OpenDroneMap services on our container-based cluster with Kubernetes as the orchestrator engine, the plan is to use the advantages of Kubernetes' powerful management capabilities to help maximize resource efficiency as the basis for creating Service Level Agreements to provide a cloud service.