Sahin Albayrak

Prof. Dr. Sahin Albayrak

Technische Universität Berlin, Berlin, Germany

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

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

Representative Publications

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11 November 2008 in Mobile Networks and Applications
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Journal Article
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ASAubrey-Derrick Schmidt
Aubrey-Derrick Schmidt
FPFrank Peters
Frank Peters
FLFlorian Lamour
Florian Lamour
CSChristian Scheel
Christian Scheel
Seyit A. CamtepeSeyit A. Camtepe
Seyit A. Camtepe
Sahin AlbayrakSahin Albayrak
Sahin Albayrak

17 July 2020 in Sensors
Verified
Journal Article
Open access
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MWMathias Wilhelm
Mathias Wilhelm
DKDaniel Krakowczyk
Daniel Krakowczyk
Sahin AlbayrakSahin Albayrak
Sahin Albayrak
Rings are widely accepted wearables for gesture interaction. However, most rings can sense only the motion of one finger or the whole hand. We present PeriSense, a ring-shaped interaction device enabling multi-finger gesture interaction. Gestures of the finger wearing ring and its adjacent fingers are sensed by measuring capacitive proximity between electrodes and human skin. Our main contribution is the determination of PeriSense’s interaction space involving the evaluation of capabilities and limitations. We introduce a prototype named PeriSense, analyze the sensor resolution at different distances, and evaluate finger gestures and unistroke gestures based on gesture sets allowing the determination of the strengths and limitations. We show that PeriSense is able to sense the change of conductive objects reliably up to 2.5 cm. Furthermore, we show that this capability enables different interaction techniques such as multi-finger gesture recognition or two-handed unistroke input.

17 April 2023 in IEEE Access
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Journal Article
Open access
MKMustafa Cagatay Kocer
Mustafa Cagatay Kocer
Ahmet ONENAhmet ONEN
Ahmet ONEN
JJJaesung Jung
Jaesung Jung
HGHakan Gultekin
Hakan Gultekin
Sahin AlbayrakSahin Albayrak
Sahin Albayrak
The radical increase in the popularity of electric vehicles (EVs) has in turn increased the number of associated problems. Long waiting times at charging stations are a major barrier to the widespread adoption of EVs. Therefore, battery swapping stations (BSSs) are an efficient solution that considers short waiting times and healthy recharging cycles for battery systems. Moreover, swapping stations have emerged as a great opportunity not only for EVs, but also for power systems, with regulation services that can be provided to the grid particularly for small networks, such as microgrid (MG) systems. In this study, the optimum location and size that maximize the revenue of a swap station in an MG system are investigated. To the best of our knowledge, this study is first to solve the placing and sizing problem in the MG from the perspective of a BSS. The results indicate that bus 23 is the BSS’s optimal location and is crucial for maximizing revenue and addressing issues like the provision of ancillary services in microgrid system. Finally, the swap demand profile of the station serving electric bus public transportation system was obtained using an analytical model based on public transportation data collected in Berlin, Germany.

29 June 2023 in International Journal of Data Science and Analytics
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Journal Article
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Shoujin WangShoujin Wang
Shoujin Wang
YWYang Wang
Yang Wang
Fikret SivrikayaFikret Sivrikaya
Fikret Sivrikaya
Sahin AlbayrakSahin Albayrak
Sahin Albayrak
Vito Walter AnelliVito Walter Anelli
Vito Walter Anelli
Data science has been the foundation of recommender systems for a long time. Over the past few decades, various recommender systems have been developed using different data science and machine learning methodologies and techniques. However, no existing work systematically discusses the significant relationships between data science and recommender systems. To bridge this gap, this paper aims to systematically investigate recommender systems from the perspective of data science. Firstly, we introduce the various types of data used for recommendations and the corresponding machine learning models and methods that effectively represent each type. Next, we provide a brief outline of the representative data science and machine learning models utilized in building recommender systems. Subsequently, we share some preliminary thoughts on next-generation recommender systems. Finally, we summarize this special issue on data science for next-generation recommender systems.

5 May 2023 in ACM Transactions on Human-Robot Interaction
Verified
Journal Article
Open access
OGO. Can Görür
O. Can Görür
BRBenjamin Rosman
Benjamin Rosman
Fikret SivrikayaFikret Sivrikaya
Fikret Sivrikaya
Sahin AlbayrakSahin Albayrak
Sahin Albayrak
A limitation for collaborative robots (cobots) is their lack of ability to adapt to human partners, who typically exhibit an immense diversity of behaviors. We present an autonomous framework as a cobot’s real-time decision-making mechanism to anticipate a variety of human characteristics and behaviors, including human errors, toward a personalized collaboration. Our framework handles such behaviors in two levels: (1) short-term human behaviors are adapted through our novel Anticipatory Partially Observable Markov Decision Process (A-POMDP) models, covering a human’s changing intent (motivation), availability, and capability; (2) long-term changing human characteristics are adapted by our novel Adaptive Bayesian Policy Selection (ABPS) mechanism that selects a short-term decision model, e.g., an A-POMDP, according to an estimate of a human’s workplace characteristics, such as her expertise and collaboration preferences. To design and evaluate our framework over a diversity of human behaviors, we propose a pipeline where we first train and rigorously test the framework in simulation over novel human models. Then, we deploy and evaluate it on our novel physical experiment setup that induces cognitive load on humans to observe their dynamic behaviors, including their mistakes, and their changing characteristics such as their expertise. We conduct user studies and show that our framework effectively collaborates non-stop for hours and adapts to various changing human behaviors and characteristics in real-time. That increases the efficiency and naturalness of the collaboration with a higher perceived collaboration, positive teammate traits, and human trust. We believe that such an extended human-adaptation is a key to the long-term use of cobots.

8 May 2024 in IEEE Access
Verified
Journal Article
Open access
PBPedram Babakhani
Pedram Babakhani
ALAndreas Lommatzsch
Andreas Lommatzsch
TBTorben Brodt
Torben Brodt
DSDoreen Sacker
Doreen Sacker
Fikret SivrikayaFikret Sivrikaya
Fikret Sivrikaya
Sahin AlbayrakSahin Albayrak
Sahin Albayrak
This paper presents a comprehensive study on generating subjective inquiries for news media posts to empower public engagement with trending media topics. While previous studies primarily focused on factual and objective questions with explicit or implicit answers in the text, this research concentrates on automatically generating subjective questions to directly elicit personal preference from individuals based on a given text. The research methodology involves the application of fine-tuning techniques across multiple iterations of flan-T5 and GPT3 architectures for the task of Seq2Seq generation. This approach is meticulously evaluated using a custom dataset comprising 40,000 news articles along with human-generated questions. Furthermore, a comparative analysis is conducted using zero-shot prompting via GPT-3.5, juxtaposing the performance of fine-tuned models against a significantly larger language model. The study grapples with the inherent challenges tied to evaluating opinion-based question generation due to its subjective nature and the inherent uncertainty in determining answers. A thorough investigation and comparison of two transformer architectures are undertaken utilizing conventional lexical overlap metrics such as BLEU, ROUGE, and METEOR, alongside semantic similarity metrics encompassing BERTScore, BLEURT, and answerability scores such as QAScore, and RQUGE. The findings underscore the marked superiority of the flan-T5 model over GPT3, substantiated not only by quantitative metrics but also through human evaluations. The paper introduces Opinerium based on the open-source flan-T5-Large model, identified as the pacesetter in generating subjective questions. Additionally, we assessed all aforementioned metrics thoroughly by investigating the pairwise Spearman correlation analysis to identify robust metrics.