Ucuk Darusalam

Particle size distribution (PSD) is a key determinant of aerosol optical properties and plays an important role in optical sensing and environmental monitoring. However, estimating PSD from light scattering measurements remains a challenging inverse problem due to its ill-posed nature and sensitivity to noise. To achieve the objective, this study proposed a physics-informed, data-driven inversion framework for PSD reconstruction using multi-angle light scattering signals generated from Mie scattering simulations. Synthetic datasets were generated using Johnson–SB, lognormal, and bimodal lognormal PSDs under various optical conditions, and the resulting scattering intensities were used to train machine learning models, including Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Support Vector Regression (SVR). The proposed framework was evaluated using both point-wise error metrics and distribution-based metrics, including Kullback–Leibler divergence and Wasserstein distance. The results showed that RF and XGBoost consistently achieved the highest reconstruction accuracy, with R² values exceeding 0.98 across different PSDs, and significantly outperformed conventional linear baseline methods, including Ridge regression (representing Tikhonov regularization) and Non-negative Least Squares (NNLS). Additional experiments using lognormal and bimodal lognormal PSDs further confirmed the distributional generalization capability of the proposed model. The reconstructed PSDs also showed strong agreement with the reference distributions and remained robust under Gaussian, lognormal, and combined noise perturbations of up to 20%. Therefore, integrating physics-based scattering simulations with machine learning provided an accurate and robust solution for the inverse Mie scattering problem in optical particle characterization.

Subject of study. A review of circuit design solutions for multiplexers used in wireless optical communication systems to increase the communication channel capacity is presented. Aim of study. The relationships between the parameters of a wireless optical communication system and the circuit solutions of a multiplexer subsystem that are optimal in terms of increasing the communication channel capacity and efficient use of the channel bandwidth are determined. Method . The increase in the capacity of a wireless optical communication system is achieved by adding a multiplexing subsystem to its structure. Optimal multiplexing schemes are determined as a result of an analytical review of various wireless optical communication systems by comparing their parameters and characteristics given in literary sources. Main results. Based on an analytical review of literary sources, which present the results of computer and physical modeling of wireless optical communication systems, multiplexing schemes have been identified, the use of which allows the throughput of an optical communication channel to be increased. Practical significance. The results of the conducted review allow, when designing a wireless optical communication line, the optimal multiplexing scheme for a given application to be selected and, accordingly, the transmission capacity to be increased and the channel bandwidth to be effectively used, satisfying the ever-growing demands of applications that require large volumes of transmitted data.

As technology develops, photography service providers are starting to move from the offline to online phase. However, the previous application was considered less than optimal in meeting user needs. The Agile Scrum method is believed to be the most appropriate for designing and building photography service applications. Because it is suitable and practical, system development using the agile method is designed and implemented. Capture is a mobile application and website that was designed because it was not available in previous research. A new feature for service providers can upload photos and cinematic videos to attract users' attention. For this reason, a mobile-based photography service system was designed using agile development methodology and testing for users and service providers.

Optical relaying is the best technique to implement free-space optical (FSO) communications as a terrestrial platform. However, atmospheric turbulence (AT) limits the optical-propagation path length. In this study, the implementation of some optical amplifiers (OAs) in cascaded configuration, namely, erbium-doped fiber amplifiers, semiconductor OAs, and Raman amplifiers (RAs), are investigated through simulation. This study aims to search for the maximum link distance of an optical propagation and enhance the FSO performance caused by each configuration of OAs. The optical relaying network consists of three nodes, with each node designed with a space of several kilometers under the influence of AT. At the end of the destination, before the receiver, an optical band-pass filter is applied to perform noise filtering. Among the OAs in the cascaded configuration, the RA can expand the link distance of the optical-propagation path length to a range of 14.7–15.9 Km under the influence of a strong AT. The signal-to-noise ratio and bit error rate of the system are in the ranges of 24.1– 19.08 dB and 7.9 × 10−15–7.4 × 10−6, respectively.

Pesantren merupakan wahana pendidikan agama Islam yang berkembang pesat dan menjadi basis dalam pendalaman ilmu fiqih dan tarbiyah. Pesantren berkembang diseluruh penjuru nusantara dengan ciri khas baik tradisional dan modern. Pesantren merupakan wahana pendidikan yang memiliki potensi dalam penerapan program lingkungan berkelanjutan atau pencapaian Sustainability Development Goals (SDGs). Dalam kegiatan pelatihan web-tracking yang telah dilakukan Tim Pengabdian kepada Masyarakat (PkM) Universitas Nasional (UNAS) melalui bentuk kerjasama dengan Pusat Pengkajian Islam (PPI-UNAS) telah berhasil dilakukan perancangan web-tracking dan workshop pemanduan penggunaan. Masalah yang dihadapi PPI-UNAS dalam upaya melakukan pemetaan potensi penerapan program lingkungan yang berkelanjutan di pesantren yakni belum tersedianya system pemetaan pesantren yang menerapkan program lingkungan dan potensi keberlanjutan penerapannya. Untuk itulah PPI-UNAS memerlukan solusi web yang berfungsi sebagai tracking program lingkungan yang dinamakan web-tracking ekopesantren. Metode perancangan web yang digunakan oleh Tim PKM UNAS adalah dengan self-assessment berbasis 10 program lingkungan. Kuesioner dalam web disusun terdiri atas 50 pertanyaan dengan jawaban skala Likert yakni scoring nilai 0 – 100. Jawaban diberikan dalam bentuk pilihan dan uraian penjelasan serta diberikan data pendukung berupa dokumentasi dan foto. Selanjutnya Tim PkM UNAS memberikan pelatihan kepada 123 peserta dari pesantren untuk uji coba penggunaan web-tracking. Metode pelatihan yang diterapkan dalam PkM adalah menggunakan metode direct coaching. Pelatihan web-tracking dilakukan di 3 kota besar yakni Medan, Bandung dan Yogyakarta pada 4 – 25 Oktober 2022. Dari hasil implementasi pada 123 peserta pesantren yang diundang dalam kegiatan workshop, web-tracking ekopesantren berhasil digunakan dengan mudah dan bersifat user friendly. Data yang diberikan oleh pesantren dapat dimasukkan ke system web-tracking dengan mudah dan menghasilkan gambaran pemetaan penerapan 10 program lingkungan. Hasil pelatihan penggunaan web dengan metode direct coaching berdasarkan penilain umpan balik peserta adalah web-tracking mudah digunakan 89,4%, pertanyaan kuesioner self-assessment relevan dengan 10 program lingkungan 97,56%, self-assessment membantu pesantren dalam pemetaan program lingkungan 88,6%, penyampaian materi jelas 90,2%, dan acara diselenggarakan panitia dengan layanan yang baik 96,7%.

This review paper discusses the complete evolution of free-space optical (FSO) communication, also known as unguided optical communication (UOC) technologies, all the way back to ancient man’s fire to today’s machine-learning-supported UOC systems. The principles, significance, and developments that have happened over the past several decades, as well as installation methodologies, technological limitations, and today’s challenges of UOCs are presented. All the subsets of UOC: FSO communication, underwater optical wireless communication (UOWC), and visible light communication (VLC), with their technology/system developments, potential applications, and limitations are reviewed. The state-of-the-art developments/achievements in (i) FSO channel effects and their mitigation techniques; (ii) radio-over-FSO techniques; (iii) wavelength division multiplexing and sub-carrier multiplexing techniques; (iv) FSO for worldwide interoperability for microwave access applications; (v) space optical satellite communication (SOSC); (vi) UWOC; (vii) photoacoustic communication (PAC); (viii) light-fidelity; (ix) VLC; (x) vehicular VLC (V²LC); and (xi) optical camera communication are reviewed. In addition, the current developments on emerging technologies such as artificial intelligence (to improve the performance of UOC systems), energy harvesting (for the effective utilization of UOC channels), and near-future communication network scenarios (mandatory for secured broadband digital links) are covered. Finally, in brief, to achieve the full potential of UOC systems, challenges that require immediate research attention are summarized.

Sinar Adventure Store is a shop that provides camping equipment, this store has many customers who want to rent camping equipment such as tents, carril bags, stoves and sling bags. But the camping equipment rental transaction at this shop still uses the conventional process, so there are still many errors that occur in writing information and data reports on this camping equipment rental. This is the author's reference in designing a web-based camping equipment rental information system, with HTML, CSS, and PHP programming languages as the database. This system is designed using the waterfall method and the system follows the flow of the Time Charter Party method. In data processing, such as recording rental transaction data, it is still stored in a ledger storage media so that data security is not guaranteed because there is no more searching for camping equipment data at the Sinar Adventure Store who still has to wait a long time because they have to find one data person in the books. The purpose of creating this rental system is to overcome the problems that are currently happening at the Sinar Adventure Store store. The results of this study are to provide convenience in the processing of camping equipment data at the Sinar Adventure Store store such as admin data, data rental, ordering, checkout and to simplify the data search process in addition to having a more effective and larger storage media.

The school is a place where the teaching and learning process takes place where the school applies virtual learning, so that students easily feel bored when learning. There are many types of learning, and the problems that arise in the learning process are also diverse. In this study, problems in the learning process were still limited, and the delivery of material provided by the teacher made it difficult for students to understand, thereby reducing student interest in learning. Responding to this situation, the temporary results of the author succeeded in creating a website and doing graphic testing on the website that was created, which only 56 users could access. If there are 100 users accessing the website, the server will be down and the website cannot be accessed by anyone.

MJT Makara Journal of Technology