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212 results on '"Sri Sumantyo, Josaphat Tetuko"'

3. 3D Traveling Ionospheric Disturbances During the 2022 Hunga Tonga–Hunga Ha’apai Eruption Using GNSS TEC

Author

Cahyadi, Mokhamad Nur, primary, Muslim, Buldan, additional, Muafiry, Ihsan Naufal, additional, Gusman, Aditya Riadi, additional, Handoko, Eko Yuli, additional, Anjasmara, Ira Mutiara, additional, Putra, Meilfan Eka, additional, Wulansari, Mega, additional, Lestari, Dwi Sri, additional, Jin, Shuanggen, additional, and Sri Sumantyo, Josaphat Tetuko, additional

Published
2024
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5. Preface

Author

Che Omar Rohayu, Sri Sumantyo Josaphat Tetuko, White Ben, Ballesteros Florencio C., and Cardenas Tristan Abraham

Subjects
Environmental sciences, GE1-350
Published
2023
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12. Preface

Author

Che Omar Rohayu, Sri Sumantyo Josaphat Tetuko, White Ben, Cardenas Tristan Abraham, Haryono Eko, Hizbaron Dyah Rahmawati, and Putri Ratih Fitria

Subjects
Environmental sciences, GE1-350
Published
2021
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13. Differentially Fed Dual-Band Base Station Antenna With Multimode Resonance and High Selectivity for 5G Applications

Author

Liu, Xuekang, Sanz-Izquierdo, Benito, Zhang, Haiwei, Gao, Steven, Hu, Wei, Yang, Xue-Xia, and Sri Sumantyo, Josaphat Tetuko

Abstract

A dual-polarized antenna with multimode resonance and high selectivity is proposed in this article to cover the 5G sub-6 GHz bands. The proposed antenna achieves dual wide impedance bandwidth characteristics by incorporating a dual mode coupled patch and four planar coupled strips around the driven patch. Through the four resonant modes of these structures, the antenna effectively covers the two desired frequency bands. Moreover, the electric/magnetic coupling between the driven patch, dual mode coupled patch, and planar coupled strips enables the creation of three radiation nulls that suppress unwanted radiation. To further improve the out-of-band rejection level and half power beamwidth (HPBW), four shorted strips are introduced around the radiator. The introduction of these strips results in a fourth radiation null at higher out-of-band frequencies and expands the antenna’s HPBW from 52° to 62°. To demonstrate the feasibility of the design, both the proposed antenna and its array were manufactured and tested. Measured results show that the filtering element was able to operate within frequency bands of 3.24–3.83 GHz (16.7%) and 4.74–5.30 GHz (11.2%) with a reference of $\vert \text{S}_{\text {dd11}} \vert < -14$ dB. The input ports exhibited a high level of isolation, measuring 40 dB. Furthermore, the four radiation nulls proved effective in suppressing out-of-band radiation.

Published
2024
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30. A Preliminary Study: Marine Biogeography of Nautilus in the Bangka Belitung Seas, Indonesia.

Author

Siti Aisyah, Sri Sumantyo, Josaphat Tetuko, Pamungkas, Aditya, Muftiadi, M. Rizza, and Muh Yusuf

Abstract

Nautilus is the only surviving genus whose members were numerous and widely dispersed in the oceans throughout the Jurassic and Miocene times. It represents the only living member from the Family Nautilidae and is often considered as a living fossil. Nautilus is found with high biodiversity in Ambon, Indonesia, and were in special cases even found in Bangka Belitung, far from their original habitat. This study aimed to understand the historical component of the habitat and distribution of Nautilus in Bangka Belitung and to determine the depth, temperature, current, and environmental heterogeneity relate to Nautilus. Nautilus samples were found in Bangka Belitung Seas nearby a crack region at 50--75 m deep while the optimal depth of the Nautilus was 150--300 m, depending on the local area. The locations in the Bangka Belitung Seas where Nautilus found have sea surface temperatures between 30-31°C and 27-28°C during the East Monsoon and the West Monsoon respectivelly. The implications of temperature as a limiting factor are fairly significant, as it restricts the upper limit of the living habitat to predictable depths, which vary both geographically and seasonally during the West Monsoon when surface temperatures approach habitable levels. Sea currents at the Bangka Belitung Seas move at 0-0.6 m.s-1 during the East Monsoon and speed up near the North Natuna Sea. During the West Monsoon, currents predominantly flow from the Natuna Sea to the Java Sea at 0-0.5 m.s-1. Large-scale deep-water currents and the effects of smaller currents on scent dispersal influence the directional movements of Nautilus. [ABSTRACT FROM AUTHOR]

Published
2021
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31. Contributors

Author

Avtar, Ram, Bhattacharya, Avik, Biswas, Mantosh, Brisco, Brian, Chaudhary Kumar, Sumit, Das, Anup Kumar, Faraslis, Ioannis N., Govil, Himanshu, Granger, Jean, Gupta, Dileep Kumar, Huggannavar, Vinayak, Indu, J., Ishikawa, Mamoru, Kaur, Ravneet, Kharrazi, Ali, Koppad, Arjun G., Krishnan, Sooraj, Kumar, Ajit, Kumar, Pankaj, Kumar, Pradeep, Kumar, Shashi, Kumar, Sourav, Kumar, Vikram, Kumar, Vineet, Kurniawan, Tonni Agustiono, Lang, Megan, Lopez-Sanchez, Juan M., Mahdianpari, Masoud, Maini, Raman, Mandal, Dipankar, Mangla, Rohit, McNairn, Heather, Mishra, Varun Narayan, Mitchell, Scott, Mohammadimanesh, Fariba, Monika, Mustak, S.K., Nair, Akhilesh S., Pal, Mahesh, Pandey, Arvind Chandra, Pandey, Varsha, Parida, Bikash Ranjan, Patel, Parul, Petropoulos, George P., Pradhan, Ankita, Prakash, Bhanu, Prasad, Rajendra, Prashar, Shivendu, Rao, Y.S., Salehi, Bahram, Sanyal, Ratna, Sarfin, Syeda, Shafiyoddin, Sayyad, Shakya, Achala, Shanker Srivastava, Hari, Sharma, Jyoti, Singh, Sartajvir, Singh, Sudhir Kumar, Singh, Rishabh, Sivasankar, Thota, Sood, Vishakha, Sri Sumantyo, Josaphat Tetuko, Srivastava, Prashant K., Suman, Swati, Tiwari, Reet Kamal, Tiwari, Umesh Kumar, Toure, Souleymane, Tripathi, Gaurav, Umarhadi, Deha Agus, Verma, Kaushlendra, Wale, Prasad Balasaheb, Widyatmanti, Wirastuti, Yadav, Suraj A., and Yunus, Ali P.

Published
2022
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41. SAR Image Processing Based on the LEON3 Multiprocessor for CP-SAR onboard Microsatellite

Author

Panggabean, Good Fried; Josaphat Microwave Remote Sensing Laboratory Center for Environmental Remote Sensing, Chiba University, Sri Sumantyo, Josaphat Tetuko; Josaphat Microwave Remote Sensing Laboratory Center for Environmental Remote Sensing, Chiba University, Setiadi, Bambang; Research Center for Geotechnology, Indonesian Institute of Sciences, Bandung, Indonesia, Panggabean, Good Fried; Josaphat Microwave Remote Sensing Laboratory Center for Environmental Remote Sensing, Chiba University, Sri Sumantyo, Josaphat Tetuko; Josaphat Microwave Remote Sensing Laboratory Center for Environmental Remote Sensing, Chiba University, and Setiadi, Bambang; Research Center for Geotechnology, Indonesian Institute of Sciences, Bandung, Indonesia

Abstract

The SAR imaging processor is an essential part in SAR system to produce the final SAR image quality that used for various remote sensing applications. In this paper, we propose the design and describe the development of onboard SAR image processor based on LEON3 softcore multiprocessor implemented on FPGA board. The proposed SAR image processor is targetted to used for future onboard Unmanned Aerial Vehicle (UAV) and microsatellite of Josaphat Microwave Remote Sensing Laboratory (JMRSL). The system-on-chip (SoC) approach has been used for highly configurable, easy to integrate with other IP core through an AMBA on-chip bus and low-cost implementation. The open hardware LEON3 multiprocessor has been configured to meet the system requirement to aim at high-performance processing. The implementation of the proposed SAR image processing is targetted on an Altera Cyclone IV FPGA family and Xilinx Artix-7 FPGA AC701 Evaluation Kit. The RDA algorithm is implemented as software to run on the LEON3 Multiprocessor, and the functionality validated using the ALOS PALSAR raw data. The preliminary results show that the functionality of the system successfully works and can compress the SAR raw data into an SAR image, whereas the processing speed needs to be improved. The proposed design promises to answer the problem of SAR image processing in the future with a low price.

Published
2018

42. Novel phase error compensation algorithm for direct digital synthesizer chirp generator in synthetic aperture radar

Author

Yang, Heein; Chiba University, Center for Environmental Remote Sensing (CEReS), Josaphat Microwave Remote Sensing Laboratory (JMRSL), Izumi, Yuta; Graduate School of Environmental Studies, Tohoku University, Japan, Sato Laboratory, Sri Sumantyo, Josaphat Tetuko; Chiba University, Center for Environmental Remote Sensing (CEReS), Josaphat Microwave Remote Sensing Laboratory (JMRSL), Yang, Heein; Chiba University, Center for Environmental Remote Sensing (CEReS), Josaphat Microwave Remote Sensing Laboratory (JMRSL), Izumi, Yuta; Graduate School of Environmental Studies, Tohoku University, Japan, Sato Laboratory, and Sri Sumantyo, Josaphat Tetuko; Chiba University, Center for Environmental Remote Sensing (CEReS), Josaphat Microwave Remote Sensing Laboratory (JMRSL)

Abstract

This paper proposes a novel phase error compensation algorithm for the direct digital synthesizer (DDS) chirp generator of high-resolution synthetic aperture radar (SAR). The proposed compensation algorithm adopts the curve fitting method to calculate the error of transmission SAR signal called chirp. In addition, this paper proposes the polynomial modeling method during chirp generation stage to improve spectrum characteristics. The mathematical equations proposed in this paper indicate that the phase shift of chirp in time domain can be eliminated clearly. Simulation results show that the proposed compensation algorithm enhances the peak-to-side lobe ratio (PSLR) and the integrated side ratio (ISLR) up to -0.2068 dB and -0.1091 dB respectively. In addition, spur components have been reduced when compared to the spectrum output of conventional DDS output.

Published
2018

43. Image processing of alos palsar satellite data, small unmanned aerial vehicle (UAV), and field measurement of land deformation

Author

kausarian, Husnul, Sri Sumantyo, Josaphat Tetuko, putra, Dewandra bagus eka, Suryadi, Adi, Gevisioner, Gevisioner, kausarian, Husnul, Sri Sumantyo, Josaphat Tetuko, putra, Dewandra bagus eka, Suryadi, Adi, and Gevisioner, Gevisioner

Abstract

Pekanbaru, Indonesia is connected by four big bridges, Siak Bridge; I, II, III and IV. The quality of the Siak bridges deteriorated seriously at this time. Geological mapping for the land subsidence potency was conducted using small Unmanned Aerial Vehicle (UAV) in the Siak Bridge areas. The study of the Siak bridges are supported by the Differential Interferometric Synthetic Aperture Radar (DInSAR) analysis using ALOS PALSAR satellite data, and the deflection observation that occurs in Siak III Bridge was observed by field measurement. The results of 3D model analysis showed that there is no negative land deformation. DInSAR analysis shows the amount of positive deformation of Siak I is 81 cm, Siak II is 48 cm, Siak III is 89 cm, and Siak IV is 92. Deflection on Siak III Bridge was detected at around 25-26 cm. These models could be used as a new way of measuring the bridge deformation on a big scale.

Published
2018

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