Cherntanomwong, Panarat
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Cherntanomwong, Panarat
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panarat.ch@kmitl.ac.th
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Item type:Publication, The comparison of optical beam tracking algorithm for free space optics(2017-10-19) ;Nakarach, NuttaponFree Space Optics (FSO) is the technology which has robustness in transmitting a large amount of data and energy efficient. However, there are other factors to make the FSO system more efficient. One of them is the optical beam tracking. This factor will use the optical alignment mechanism to align the optical transceiver to the maximum power point. In order to maximize the power, the tracking algorithm will apply to the mechanism. In this study these tracking algorithms which are simple peaking, step track algorithm (gradient method) and 4 Quadrant Detectors were used to peak the transponder to the maximum energy position. The simulation results show the processing time and efficiency for each algorithm. This result also shows that which algorithm is suitable for which free space optics application. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, TLB and WC-TLB-MM: The Improved Min-Max Algorithms for Multi Targets Indoor Localization(2023-01-01) ;Adiyatma, Farid Yuli Martin ;Suroso, Dwi JokoInternet of Things (IoT)-based Indoor localization is the most commonly used system to determine target locations indoors. It applies to various purposes, e.g., indoor navigation, asset tracking in warehouse management, and tracking people in hospitals. Distance-based techniques using the Received Signal Strength Indicator (RSSI), e.g., Min-Max, are widely applied because they can be directly implemented without prerequisite work such as site surveys. However, a challenging indoor environment with high numbers of interiors and people can obstruct signal propagation. This obstruction can reduce the accuracy of translating RSSI to distance using the path loss model, which will degrade the localization accuracy. In this paper, we introduce two improved Min-Max (MM) algorithms, i.e., Three Layer Bounding Box Min-Max (TLB-MM) and Weighted Centroid TLB-MM (WC-TLB-MM), to alleviate the issue and achieve higher localization accuracy. The novelty of the proposed TLB-MM is incorporating RSSI error functions to generate three-layer bounding boxes: the inner, middle, and outer in the Min-Max algorithm. Meanwhile, WC-TLB-MM enhanced the TLB-MM algorithm by integrating the Weighted Centroid Localization Algorithm (WCLA) in the calculation process. We validate our proposal by conducting various experiments using Wi-Fi at 2.4 GHz deployed in a laboratory room of 10.17 m ×9.12 m. Experimental results demonstrate that TLB-MM improved the accuracy performance to 55.78% and 30.86%, while WC-TLB-MM gave 40.93% and 7.65% compared to Min-Max and WCLA, respectively. From these results, our proposed methods are proven simple yet applicable to RSSI-based indoor localization systems. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Fingerprint Database Enhancement by Applying Interpolation and Regression Techniques for IoT-based Indoor Localization(2020-01-01) ;Suroso, Dwi Joko ;Adiyatma, Farid Yuli Martin; Most applied indoor localization is based on distance and fingerprint techniques. The distance-based technique converts specific parameters to a distance, while the fingerprint technique stores parameters as the fingerprint database. The widely used Internet of Things (IoT) technologies, e.g., Wi-Fi and ZigBee, provide the localization parameters, i.e., received signal strength indicator (RSSI). The fingerprint technique advantages over the distance-based method as it straightforwardly uses the parameter and has better accuracy. However, the burden in database reconstruction in terms of complexity and cost is the disadvantage of this technique. Some solutions, i.e., interpolation, image-based method, machine learning (ML)-based, have been proposed to enhance the fingerprint methods. The limitations are complex and evaluated only in a single environment or simulation. This paper proposes applying classical interpolation and regression to create the synthetic fingerprint database using only a relatively sparse RSSI dataset. We use bilinear and polynomial interpolation and polynomial regression techniques to create the synthetic database and apply our methods to the 2D and 3D environments. We obtain an accuracy improvement of 0.2m for 2D and 0.13m for 3D by applying the synthetic database. Adding the synthetic database can tackle the sparsity issues, and the offline fingerprint database construction will be less burden. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Dynamic Ensemble Learning With Received Signal Strength Transformation for Robust Multi-Floor Wi-Fi Indoor Localization(2026-01-01) ;Yuli Martin Adiyatma, Farid; Joko Suroso, DwiReceived Signal Strength (RSS)-based Wi-Fi localization offers a cost-effective solution for multi-floor indoor location estimation. However, its accuracy is often degraded by signal fading, multipath propagation, and device heterogeneity, posing major challenges to reliable localization. Recent studies have increasingly employed deep neural networks due to their ability to extract meaningful patterns from RSS data; however, these models require substantial computational resources and extensive parameter tuning, which limits their adaptability across diverse dynamic environments. To address these limitations, we propose DELLoc-RT, a localization framework integrating Dynamic Ensemble Learning (DELLoc) with RSS Transformation (RT) for accurate, efficient, and adaptable multi-floor indoor localization. The RT module applies Sigmoid-scaled normalization and confidence weighting to convert RSS values into compact, learnable features. DELLoc employs multiple base learners optimized via the Tree-structured Parzen Estimator with a pruning strategy (TPE-PS) that accelerates convergence by focusing on promising configurations. Additionally, Iterative Ensemble Optimization with Stepwise Selection (IEO-SS) selects complementary learners to enhance overall performance. Experimental results demonstrate that DELLoc-RT achieves floor classification accuracies of 93.32%, 94.38%, and 94.02% on the UJIIndoorLoc, UTSIndoorLoc, and Tampere datasets, respectively, with mean Euclidean errors (MEE) of 10.63 m, 7.87 m, and 8.19 m. These results highlight the model’s strong adaptability across diverse datasets. Evaluation on a self-constructed dataset further confirms that DELLoc-RT delivers high accuracy and efficiency while substantially reducing the need for manual tuning, enabling rapid deployment in practical scenarios. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Implementation of Wi-Fi-based indoor positioning system: Challenges and future possibilities(2023-11-20) ;Suroso, Dwi Joko ;Adiyatma, Farid Yuli Martin; Radiofrequency (RF)-based technologies are utilized as the core of indoor positioning system (IPS), i.e., Wi-Fi, Bluetooth, radio frequency identification (RFID), ultrawideband (UWB), and ZigBee standard. Wi-Fi is the most promising technology because of its wide availability on any smart or personal device and comes at a relatively low cost. Considering Wi-Fi technology as the core of IPS, there are several challenges related to positioning performance in its research and implementation. Nowadays, most real applications and implementations of Wi-Fi-based indoor positioning use the received power signal, the received signal strength indicator (RSSI). The position and time accuracy can determine the IPS system's performance. In the actual implementation, we must consider the specific position at that specific time (real-time system). From some references on IPS systems, most research is likely divided into two types; the algorithm development is somehow not a real-time implementation and proposal to implement in an actual application. This paper aims to study the real implementation of Wi-Fi-based IPS development, its recent advances, methods, performance requirements, challenges, and limitations, and, finally, offer the possibility for the prospective IPS research topics. Some future possibilities include the signal optimization algorithm, the new method with artificial intelligence, machine, or deep learning for Wi-Fi-based device-free IPS. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Is Deep Diffusion Probabilistic Model Applicable for Fingerprint-based Indoor Localization?(2022-01-01) ;Suroso, Dwi Joko; The latest deep learning (DL) phenomenon is the Denoising Diffusion Model (DDM). DDM is in a class of latent variable models of the deep generative model (DGM) along with the big name of Generative Adversarial Networks (GANs) and Variational Autoencoders (VAEs). Moreover, in a recent finding, DDM beats GANs in image synthesis. This paper presents the prospective applicability discussion of DDM for indoor localization research as previous models, e.g., GANs and VAEs, which are successfully implemented. Here, we focus more on how DDM can synthesize localization parameters with the help of fingerprinting technique's database enhancement. The fingerprint technique needs a preconstructed database which has the main drawbacks of its cost, time inefficient, and high complexity. We found valuable works of literature on this specific topic for GANs and VAEs. However, there are few DDM applications for discrete data types, and as the authors' concern, there is no attempt to apply them to indoor localization yet. DDM implementation is to generate continuous data domains, e.g., image, text, and audio data. A radio map or fingerprint database is essentially needed for fingerprint-based indoor localization. Learning this database pattern helps increase the system's performance. Obtaining a high-density and quality database is expensive and challenging to implement. Then, it raises a question, is DDM applicable for synthesizing this database and alleviating this problem? - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Indoor Device-free Localization Using Received Signal Strength Indicator and Illuminance Sensor for Random-forest-based Fingerprint Technique(2021-01-01) ;Suroso, Dwi Joko; Indoor device-free localization (IDFL) offers more flexibility than conventional indoor localization (device-based) systems, as the targets or objects need not be equipped with any device to be located. In the process of IDFL, the target is passive, enabling applications such as monitoring of elderly people, security systems to detect intruders, and indoor navigation. Despite having more flexibility than device-based systems, IDFL is still inferior in terms of localization performance. The most commonly used technique for IDFL is the fingerprint technique, which uses the uniqueness of spatial information to predict the target's location. The spatial information is a fingerprint database containing information on locations and their corresponding parameters. The most specific parameter for the fingerprint database is the received signal strength indicator (RSSI). RSSI can be obtained directly from many low-cost devices, i.e., Wi-Fi-based devices, without the need to install additional hardware. The fingerprint technique is a two-phase process: The database is constructed in the offline phase, and a matching process to compare the target's current parameter with those in the database is performed in the online phase. We propose fingerprint-technique-based IDFL using RSSI and illumination from an illuminance sensor as the additional parameters of the fingerprint database. Both parameters are recorded by considering two scenarios: An empty room and a person standing in the fingerprint grids. The constructed database is the person-filled room subtracted from the empty room database. We use random forest, one of the machine learning (ML) algorithms, as the pattern-matching algorithm. We evaluate its performance by comparison with two other ML algorithms: K-nearest neighbor (k-NN) and neural networks (NN). The results show that k-NN has better accuracy than the random forest for learning and testing in terms of the root mean square error (RMSE). On the other hand, the random forest has better accuracy than NN and better precision than either k-NN or NN for learning and testing in terms of the standard deviation (STD). The results show the possibility of improving the IDFL performance by adding more parameters to the fingerprint database and using an ML-based pattern-matching algorithm. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Signal subspace interpolation from discrete measurement samples In constructing a database for location fingerprint technique(2009-01-01); ;Takada, Jun IchiTsuji, HiroyukiIn this paper, a method of the signal subspace interpolation to constructing a continuous fingerprint database for radio localization is proposed. When using the fingerprint technique, enhancing the accuracy of location estimation requires very fine spatial resolution of the database, which entails much time in collecting the data to build up the database. Interpolated signal subspace is presented to achieve a fine spatial resolution of the fingerprint database. The angle of arrival (AOA) and the measured signal subspace at known locations are needed to obtain the interpolated signal subspaces. The effectiveness of this method is verified by an outdoor experiment and the estimated location using this method was compared with those using the geometrically calculated fingerprint and the measured signal subspace fingerprint techniques. Copyright © 2009 The Institute of Electronics, Information and Communication Engineers. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Fingerprint-based technique for indoor localization in wireless sensor networks using Fuzzy C-Means clustering algorithm(2011-12-01) ;Suroso, Dwi Joko; ; Takada, Jun IchiZigBee as IEEE 802.15.4 standard has been using for main research topic in the wireless sensor network (WSN) applications. The new method of radio frequency (RF) fingerprint-based technique for indoor localization is proposed. The received signal strength indicator (RSSI) is used as database values which correspond to the location of the sensor nodes. Fuzzy C-Means (FCM) clustering algorithm is applied as the experiment data cluster method. FCM algorithm is deployed to cluster the obtained feature vectors into several classes corresponding to the different amount of RSSI values. The results show that FCM can cluster the target node in a group of the fingerprint database. The location of target node is arranged in various forms to validate the accuracy of the clustering technique. Euclidean distance is used as the parameter to compare the similarity between fingerprint database and the target location. The results show that the new method is simple and effective method to reduce the complexity and to support the low power and to reduce the time using in the fingerprint-based localization technique. © 2011 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Step track algorithm in Free Space Optics(2015-01-01) ;Nakarach, NuttaponFree Space Optics (FSO) are going to be popular in a variety of the communications due to the higher bandwidth and data rate compared with the microwave communication systems. However, there are other factors to make the FSO system more efficient. One of them is the beam alignment. In this paper, the transponder alignment for FSO is investigated. In this paper the gradient technique, one of step track algorithm, employed for transponder alignment. The simulation results show that the gradient technique can be used for beam alignment of the optical transponder.
