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Journal articles on the topic 'FSO'

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Published: 4 June 2021
Last updated: 24 January 2023

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1

Shimamura, Yoshihide. "FPSO/FSO: State of the art." Journal of Marine Science and Technology 7, no. 2 (September 1, 2002): 59–70. http://dx.doi.org/10.1007/s007730200013.

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2

Jeong, Dae-Kyo, Cheol-Sun Park, and Dongwoo Kim. "Secrecy Outage of Threshold-Based FSO/RF-FSO Switching Systems." Journal of Korean Institute of Communications and Information Sciences 45, no. 12 (December 31, 2020): 2094–98. http://dx.doi.org/10.7840/kics.2020.45.12.2094.

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3

Bag, Banibrata, Akinchan Das, Imran Shafique Ansari, Ales Prokes, Chayanika Bose, and Aniruddha Chandra. "Performance Analysis of Hybrid FSO Systems Using FSO/RF-FSO Link Adaptation." IEEE Photonics Journal 10, no. 3 (June 2018): 1–17. http://dx.doi.org/10.1109/jphot.2018.2837356.

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4

Ladesi, Vivian Karim. "APLIKASI ANALISIS KEANDALAN PADA KEKUATAN PELAT FLOATING STORAGE OFFLOADING (FSO) DENGAN MEMAKAI SIMULASI MONTE CARLO." Menara: Jurnal Teknik Sipil 1, no. 1 (January 8, 2006): 13. http://dx.doi.org/10.21009/jmenara.v1i1.7816.

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Analisis keandalan akhir-akhir ini semakin banyak yang menggunakanya seiring dengan perkembangan ilmu pengetahuan dan teknologi. Bukan saja diaplikasikan pada bidang statistik yang menjadi induknya tetapi juga diberbagai bidang terutama pada analisis struktur yang erat hubungannya dengan peramalan dan analisa resiko. Floating Storage Offloading (FSO) merupakan struktur terapung di lautan seperti kapal tanker yang berfungsi untuk melakukan bongkar muat minyak. Dengan keberadaan FSO di lingkungan laut di mana tingkat ketidak pastian yang begitu tinggi maka analisis keandalan merupakan faktor penting yang seharusnya dilakukan. Dengan bantuan metode simulasi Monte Carlo maka analisis ini dapat dilakuan. Analisa Monte Carlo akan memberikan hasil yang dapat dijadikan rekomendasi dalam menganalisa kekuatan FSO. Metodologi yang dipakai untuk melakukan analisa ini adalah mengumpulkan data, menetapkan ambang batas keselamatan, menentukan karasteristik peubah dasar, dan kemudian melakukan simulasi Monte Carlo. Dengan demikian maka sesungguhnya analisis keandalan ini dapat diterapkan pada tahap-tahap perancangan dan perencanaan FOS atau kapal-kapal lain.
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Basahel, Ahmed, Md Rafiqul Islam, Mohamed Habaebi, and Suriza Ahmad. "Availability Prediction Methods for Terrestrial Free-Space-Optical Link Under Tropical Climate." Indonesian Journal of Electrical Engineering and Computer Science 10, no. 1 (April 1, 2018): 224. http://dx.doi.org/10.11591/ijeecs.v10.i1.pp224-229.

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<p>Free-space optical (FSO) links provide high speed point-to-point wireless communication, but its availability can easily be affected by weather conditions. In heavy rainfall regions, FSO links are relatively sensitive to rain. Availability prediction of FSO is indispensable part, especially in tropical areas. In this paper, methods to predict FSO link availability are presented. The overall performance of FSO link is described in terms of the availability that can be achieved over anticipated link distance. The availability prediction methods demonstrated for an FSO link ranges up to 5 km. The availability prediction methods are based on long-term statistics of atmospheric attenuations and FSO link budget under tropical climate condition. In tropical regions, for a terrestrial FSO link, carrier class availability can be achieved over a few hundred meters only; whereas enterprise class availability can be achieved over a few kilometers link distances. </p>
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VERMA, NISHA, M. P. SINGH, AMIT NATH, POONAM KASHYAP, S. P. SINGH, and A. S. PANWAR. "Feminine farm operational methods, involvement, hardships and sensitivity in farming systems analysis." Indian Journal of Agricultural Sciences 90, no. 1 (March 2, 2020): 96–101. http://dx.doi.org/10.56093/ijas.v90i1.98552.

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The present study has been conducted to identify the sensitivity in the pre-dominant farming systems of Western plain zone of Uttar Pradesh (WPZ) considering the importance of gender specific technologies much needed for better efficiency and productivity of farming systems. Four pre-dominant farming systems have been identified in WPZ of Uttar Pradesh with the highest area share (57.1%) and highest farmer distribution (62.9%) in FS1: Crop + Dairy (1C+1-2B). The highest net return was found in FS2: Crop + Horticulture (Fruits) + Dairy (2C+ 1-2 B), whereas the lowest net return was noticed in FS3: Crop + Horticulture (Vegetables) + Dairy (1C + 1B). Load carrying through head load was found extensively performed by the women of FS3 followed by FS4: Horticulture + Crop + Dairy (1C+1B) and FS2 respectively. Chopper (hand tool) for chaff cutting, winnowing through natural wind, power operated winnowing without safety gadgets was performed in FS4 (33%), FS3 (22.8%) and FS4 (17%) respectively by family female workers. Threshing through hand beating was maximally performed by FS2 (81%) as hired female labour. Work involvement in farming system studies shows that female workers (family and hired) of FS3 contributed maximum (44.7%) followed by FS1 (41.5%). Also, the women participation index on drudgery prone activities was found highest amongst female workers (family and hired) of FS3 (87.8%) followed by FS1 (83.21%). The results indicate that FS3 may be tagged as sensitive farming system with respect to maximum number of female headed households contributing maximum work and hardships followed by FS1.
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7

Alatawi, Ayshah S., Albashir A. Youssef, Mohamed Abaza, Mohammad Ammad Uddin, and Ali Mansour. "Effects of Atmospheric Turbulence on Optical Wireless Communication in NEOM Smart City." Photonics 9, no. 4 (April 15, 2022): 262. http://dx.doi.org/10.3390/photonics9040262.

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The foundation of any smart city requires an innovative and robust communication infrastructure. Many research communities envision free-space optical communication (FSO) as a promising backbone technology for the services and applications provided by such cities. However, the channel through which the FSO signal travels is the atmosphere. Therefore, the FSO performance is limited by the local weather conditions. The variation in meteorological variables leads to variations of the refractive index along the transmission path. These index inhomogeneities (i.e., atmospheric turbulence) can significantly degrade the performance of FSO systems. Thus, a practical implementation of the FSO link must carefully consider the atmospheric turbulence effect. This paper aims to investigate the feasibility of FSO communication for NEOM, a promising smart city in Saudi Arabia. We study the effect of weather conditions on FSO links using the micrometeorology model, taking into account actual weather data. The FSO performance in winter and summer was compared in terms of the bit error rate, signal-to-noise ratio (SNR), link availability, and transmission distance. The study shows that the atmospheric turbulence strength is moderate and strong in winter and summer, respectively. The temperature has the biggest impact on the FSO system when compared to the other meteorological elements included in this study. Furthermore, at transmission distances less than 300 m, atmospheric turbulence does not significantly affect the FSO for the operating wavelength of 1550 nm. Furthermore, it has been shown that at transmission distances greater than 300 m, the SNR in summer is more than 18% higher than in winter. The findings of this research enable understanding of the effect of turbulence caused by NEOM weather on the FSO link, thus assisting engineers in establishing a reliable FSO backbone link by adjusting the relevant parameters.
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8

Gao, Guoying, Wei Chu, Zhonglin Chen, and Jimin Shen. "Catalytic ozonation of diclofenac with iron silicate-loaded pumice in aqueous solution." Water Supply 17, no. 5 (March 29, 2017): 1458–67. http://dx.doi.org/10.2166/ws.2017.048.

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The catalytic ozonation of diclofenac (DCF) with iron silicate-loaded pumice (FSO/PMC) in aqueous solution was investigated. FSO/PMC was synthesized by a co-precipitation–impregnation method and characterized using scanning electron microscope, N2 adsorption–desorption, X-ray fluorescence, and pHpzc measurements. Results showed that the FSO/PMC/O3 process obviously improved total organic carbon (TOC) removal efficiency from 32.3% (using sole ozonation) to 73.3% in 60 min. DCF mineralization in various oxidation processes was found to follow a two-stage pseudo-first-order kinetics. The presence of FSO/PMC effectively improved the mass transfer of ozone from gas to liquid phase and increased the efficiency of ozone decomposition, which results in the formation of •OH radicals. The ozonation of DCF generated large amounts of the ozone-refractory carboxylic acids, and these compounds were found to be continuously removed in the FSO/PMC/O3 process due to the catalytic activity of FSO/PMC. The synergetic effect between ozonation and FSO/PMC adsorption indicated that FSO/PMC is a promising catalyst for the ozonation process.
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9

Tashkandi, Bayan, Ghaidaa Baghdadi, and Azza Baghdadi. "Protective Impact of Flaxseed Oil against Acetaminophen-Induced Nephrotoxicity in Rats: Antioxidant and Anti-inflammatory Pathway." Journal of Complementary Medicine Research 14, no. 1 (2023): 36. http://dx.doi.org/10.5455/jcmr.2023.14.01.11.

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Acetaminophen (AAP) is a commonly analgesic found in numerous non-prescription pharmaceuticals. High dose and chronic ingestion of AAP caused renal toxicity. This study is designed to assess the possible nephroprotective role of flaxseed oil (FSO) in male rats. Nephrotoxicity was induced in rats via ingested a single dose of AAP (3 g/kg). Five groups of rats were used; Control, AAP, FSO (1.5 ml/kg) + AAP, FSO (3 ml/kg) + AAP, and FSO (4.5 ml/kg) + AAP. Rats were received orally FSO for 30 days and at the 30th day received AAP 1 h before FSO. Serum renal function indices were determined. Also, antioxidants, oxidative stress, and pro-inflammatory cytokines indices were measured in serum. Ingestion of FSO (3 and 4.5 ml/kg) prior to AAP intoxication significantly decreased AAP-induced nephrotoxicity as evidenced by significant decrease in renal functions relative to the AAP group. Prevented the oxidative stress as evidenced by significant increases in SOD and GSH levels, concurrent with a significant decline in MDA level. Besides, there were significant decreases in IL-1α and TNF-α relative to the AAP group. FSO (3 and 4.5 ml/kg) preserved the renal parenchyma, glomerulus and tubules histological features induced by AAP. FSO (4.5 ml/kg) was markedly the most effective dose relative to the two other doses. In conclusion, FSO protects AAP-induced renal toxicity in a dose dependent manner via its potent antioxidant and anti-inflammatory activities.
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10

Gueye, Ibrahima, Ibra Dioum, Idy Diop, K. Wane Keita, Papis Ndiaye, Moussa Diallo, and Sidi Mohamed Farssi. "Performance of Hybrid RF/FSO Cooperative Systems Based on Quasicyclic LDPC Codes and Space-Coupled LDPC Codes." Wireless Communications and Mobile Computing 2020 (December 30, 2020): 1–15. http://dx.doi.org/10.1155/2020/8814588.

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Free space optical (FSO) communication systems provide wireless line of sight connectivity in the unlicensed spectrum, and wireless optical communication achieves higher data rates compared to their radio frequency (RF) counterparts. FSO systems are particularly attractive for last mile access problem by bridging fiber optic backbone connectivity to RF access networks. To cope with this practical deployment scenario, there has been increasing attention to the so-called dual-hop (RF/FSO) systems where RF transmission is used at a hop followed by FSO transmission to another. In this article, we study the performance of cooperative transmission systems using a mixed RF-FSO DF (decode and forward) relay using error-correcting codes including QC-LDPC codes at the relay level. The FSO link is modeled by the gamma-gamma distribution, and the RF link is modeled by the Additive White Gaussian Noise (AWGN) model. Another innovation in this article is the use of cooperative systems using a mixed FSO/RF DF relay using quasicyclic low-density parity check (QC-LDPC) codes at the relay level. We also use the space-coupled low-density parity check (SC-LDPC) codes on the same scheme to show its importance in cooperative optical transmission but also in hybrid RF/FSO transmission. The latter will be compared with QC-LDPC codes. The use of mixed RF/FSO cooperative transmission systems can improve the reliability and transmission of information in networks. The results demonstrate an improvement in the performance of the cooperative RF/FSO DF system based on QC-LDPC and SC-LDPC codes compared to RF/FSO systems without the use of codes, but also to the DF systems proposed in the existing literature.
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11

Khalid, Hira, Sajid Sheikh Muhammad, Hector E. Nistazakis, and George S. Tombras. "Performance Analysis of Hard-Switching Based Hybrid FSO/RF System over Turbulence Channels." Computation 7, no. 2 (June 6, 2019): 28. http://dx.doi.org/10.3390/computation7020028.

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The hybrid system of free space optic (FSO) and radio frequency (RF) has come forth as alternative good solution for increasing demand for high data rates in wireless communication networks. In this paper, wireless networks with hard-switching between FSO and RF link are analyzed, assuming that at a certain time point either one of the two links are active, with FSO link having higher priority. As the signal-to-noise ratio (SNR) of FSO link falls below a certain selected threshold, the RF link is activated. In this work, it is assumed that the FSO link follows Gamma-Gamma fading due to the atmospheric turbulence effect whereas RF link experiences Rayleigh fading. To analyze the proposed hybrid model, analytical expressions are derived for the outage probability, bit error rate and ergodic capacity. A numerical comparison is also done between the performances of the proposed hybrid FSO/RF model and the single FSO model.
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12

Soni, Gaurav. "A Performance Analysis of Free-Space Optical Link at 1,550 nm, 850 nm, 650 nm and 532 nm Optical Wavelengths." Journal of Optical Communications 39, no. 3 (June 26, 2018): 335–41. http://dx.doi.org/10.1515/joc-2016-0118.

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Abstract Free Space Optics (FSO) communication technique is a unique method for the communication between optical transmitter and optical receiver using a free space as a medium. The advantages of FSO over other wireless communication techniques is its low power, high security, low cost infrastructure, high data rates and unlicensed spectrum. There are many atmospheric disturbances like rain, fog, water molecules particles which degrade the performance of the FSO Link. In this paper, the FSO Link is optimized at different optical wavelengths of 1550 nm, 850 nm, 650 nm and 532 nm keeping into consideration the various atmospheric challenges and weather conditions. The performance of the proposed FSO link is evaluated in terms of BER and Quality factor. Simulation results for the proposed FSO link achieve maximum link range of 1000 m at 1550 nm. The achieved values of Bit Error Rate (BER) and Quality Factor (Q) for FSO link at 1550 nm are 10e-9 and 5.58 respectively.
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13

Grdiša, Martina, Nina Jeran, Filip Varga, Tatjana Klepo, Tonka Ninčević, and Zlatko Šatović. "Accumulation Patterns of Six Pyrethrin Compounds across the Flower Developmental Stages—Comparative Analysis in Six Natural Dalmatian Pyrethrum Populations." Agronomy 12, no. 2 (January 19, 2022): 252. http://dx.doi.org/10.3390/agronomy12020252.

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Pyrethrin is a specialized metabolite of Dalmatian pyrethrum (Tanacetum cinerariifolium (Trevir.) Sch. Bip.), Asteraceae, known worldwide as an effective bioinsecticide. It consists of six active compounds: Pyrethrin I and II, cinerin I and II, and jasmolin I and II. Pyrethrin accumulates mainly in the flower heads and its content depends on numerous factors, such as the flower developmental stage. This study aims to investigate the accumulation patterns of six pyrethrin compounds in the flower heads of Dalmatian pyrethrum over the eight developmental stages (FS1 to FS8), and to make a comparison in six natural populations. Ultrasound assisted extraction was used to extract the pyrethrin, while qualitative and quantitative analysis was performed by High performance liquid chromatography. The accumulation patterns of different pyrethrin compounds were generally similar and also synchronous between different populations, while the pyrethrin I/pyrethrin II ratio showed irregular patterns. In all populations studied, the highest increase of all compounds was observed from FS1 to FS2. Their concentration continuously increased, reaching the highest values at FS4 stage (2–5 rows of open disc flowers), and generally decreased gradually towards FS6 or FS7 and then stagnated until the FS8 stage. Despite the very similar accumulation pattern of pyrethrin compounds in the different populations, the significant differences in their content suggest a different genetic background. Knowledge of the dynamics of pyrethrin compounds accumulation across flower development stages is valuable for determining the optimal harvest time of pyrethrum flower heads.
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14

Li, Ming, Pengxin Zhang, and Jiawei Han. "Methods of Atmospheric Coherence Length Measurement." Applied Sciences 12, no. 6 (March 15, 2022): 2980. http://dx.doi.org/10.3390/app12062980.

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Free-space optical (FSO) communication possesses the advantages of high security, large information capacity, high-speed transmission, small terminal size, low power consumption, easy and flexible deployment, etc. It is a promising communication technique, and could be an alternative to optical fiber communication and traditional radio frequency (RF) communication. One of principal challenges that FSO faces is the susceptibility of the atmospheric channel, which is turbulent in nature. After the optical signals propagate over the atmospheric channel, their wavefronts suffer from deleterious perturbation, thus resulting in degradation in the performance of the FSO. This knowledge with respect to FSO links helps to optimize the system design and reduce the adverse effects of atmospheric turbulence. The atmospheric coherence length of FSO links reflects the atmospheric turbulence effects, and it is one of the key parameters of FSO systems. Measuring the atmospheric coherence length, as a result, is of great interest as well as importance to the FSO community. In this paper, several methods associated with atmospheric coherence length measurement are reviewed.
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Rani, Monika, Harbax Singh Bhatti, and Vikramjeet Singh. "Analysis of Atmospheric Turbulence on Free Space Optical System using Homotopy Perturbation Method." Journal of Optical Communications 40, no. 4 (October 25, 2019): 441–46. http://dx.doi.org/10.1515/joc-2017-0099.

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AbstractFree Space Optics (FSO) is a wireless optical communication technology which depends on propagation of optical beam through air. FSO communication system provides secure communication link, cost-effective solution and license-free operation. In this paper, the FSO communication link has been analysed in turbulent atmosphere using homotopy perturbation method (HPM). We have designed a FSO system operating at an optical wavelength of 850 nm with a signal power of 4 dBm having a link range of 2 km between transmitter and receiver unit. It has been observed that in atmospheric turbulence high performance FSO link is achieved by increasing the aperture diameter of receiver telescope.
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16

Mani, Vinoth Kumar, and Vinod Kumar. "Free-space optical channel performance under atmospheric losses using orthogonal frequency division multiplexing." Indonesian Journal of Electrical Engineering and Computer Science 25, no. 3 (March 1, 2022): 1571. http://dx.doi.org/10.11591/ijeecs.v25.i3.pp1571-1579.

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<span>Free space optics (FSO) is a fast-growing technology that outperforms fiber optics in communication network infrastructure without spectrum licensing. The goal of this work is to evaluate the performance of the FSO communication system using direct detection 4-quadrature amplitude modulation (4-QAM) and 4-phase shift keying (4-PSK) with orthogonal frequency division multiplexing (OFDM) scheme. Simulating a direct detection OFDM-FSO system and comparing constellation diagrams, electrical power, and optical power have been used to conduct the analysis. The model is validated using a constellation diagram of received signals for various FSO channel ranges and weather conditions. According to simulation results, the OFDM-FSO architecture combined with the 4-QAM modulation technique produces the most efficient output with the least amount of power consumption for data rates up to 10 Gb/s and FSO channel ranges of up to <br /> 3 km for clear air, 1.7 km, and 1.3 km for thin and thick fog, and 0.7 km for heavy fog. This investigation can enhance the current fiber optic network's structure connected with the FSO system to provide last-mile connectivity in 5G modules.</span>
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17

Demir, Pelin, and Güneş Yılmaz. "Investigation of the Atmospheric Attenuation Factors in FSO Communication Systems Using the Taguchi Method." International Journal of Optics 2020 (March 12, 2020): 1–8. http://dx.doi.org/10.1155/2020/9038053.

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In this study, Mie and Rayleigh scattering in free space optics (FSO) communication systems were investigated in terms of the atmospheric attenuation. Because of the movement of the Earth, the communication distance and surrounding gas densities are inconsistent in each region. This change leads to atmospheric attenuation and then data losses and inefficient communication in FSO occur. Therefore, the density change and distance must be calculated in each communication once the data is transmitted. In the literature, it was observed that the atmospheric attenuation is regarding some FSO communication parameters such as transmission distance, visibility, and scatter particle size distribution, the number of particles per unit volume, scatter cross-sectional area, and wavelength. Besides, in real-time communication, it is necessary to update FSO parameters simultaneously. However, this updating process for all parameter takes a long time to adapt to a new position. This paper proposes the design of the experiment method (Doe) to determine the severity of the FSO parameters. And Taguchi’s Doe method allows analyzing of FSO communication system parameters to avoid long calculation time. Results show that the proposed method helps in understanding the priorities of the parameters in FSO and reducing the updating time.
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18

Sekine, Seiji, Shiho Sasanuki, Yoshihiro Murano, Toshiaki Aoyama, and Hiroyuki Takeuchi. "α-Linolenic Acid-Rich Flaxseed Oil Ingestion Increases Plasma Adiponectin Level in Rats." International Journal for Vitamin and Nutrition Research 78, no. 45 (May 1, 2008): 223–29. http://dx.doi.org/10.1024/0300-9831.78.45.223.

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Adiponectin, an adipose-specific secretory protein, exhibits antidiabetic and antiatherogenic properties. The effect of α-linolenic acid (ALA) on adiponectin has not been revealed. ALA is included abundantly in vegetable oils such as flaxseed oil. In this study, we attempted to clarify the effect of ALA-rich flaxseed oil (FSO) intake on the adiponectin level in rats. Seven-week-old male Sprague-Dawley rats were fed test diets containing high oleic safflower oil (HOSO) or FSO for 4 weeks. After the experimental period, the plasma adiponectin concentration in the FSO-fed group was higher than that in the HOSO-fed group. The adiponectin content of perirenal adipose tissue in the FSO-fed group was also significantly higher than that in the HOSO-fed group. However, the adiponectin mRNA level in the perirenal adipose tissue did not differ significantly between the HOSO-fed and FSO-fed groups. In this study, we clarified the effect of the ALA-rich FSO ingestion on the plasma adiponectin concentration in rats. It was suggested that the ALA-rich FSO intake might exhibit beneficial effects through an increase of the adiponectin level.
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19

Kumar, Kuldeep, and Deva K. Borah. "Quantize and Encode Relaying Through FSO and Hybrid FSO/RF Links." IEEE Transactions on Vehicular Technology 64, no. 6 (June 2015): 2361–74. http://dx.doi.org/10.1109/tvt.2014.2343518.

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20

Makki, Behrooz, Tommy Svensson, Koen Buisman, Joaquin Perez, and Mohamed-Slim Alouini. "Wireless Energy and Information Transmission in FSO and RF-FSO Links." IEEE Wireless Communications Letters 7, no. 1 (February 2018): 90–93. http://dx.doi.org/10.1109/lwc.2017.2755658.

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21

Patimah, Ai Siti, Sigit Heru Murti, and Agus Prsaetya. "Dampak Penurunan Kualitas Air Laut Dari Kegiatan Operasi Floating Storage and Offlaoding (FSO) Challenger Lepas Pantai Blok Bawean." Jurnal Ilmu Lingkungan 20, no. 3 (March 10, 2022): 484–93. http://dx.doi.org/10.14710/jil.20.3.484-493.

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Floating Storage and Offloading (FSO) terletak pada koordinat 6° 43’51.84” LS dan 112° 09’19.84” BT berada di Blok Bawean. Fasilitas FSO adalah tanker pengangkut dan penyimpan crude oil dengan kapasitas 900.000 barrel. Penelitian ini bertujuan untuk (1) mengetahui parameter kualitas air laut di FSO Challenger semester II 2018 (2) mengevaluasi kecenderungan dan tingkat kekritisan kualitas air laut di FSO Challenger tahun 2015-2018. Lokasi penelitian pada bagian Up stream dan Down stream FSO Challenger, parameter yang diuji yaitu kekeruhan, TSS, suhu, pH, BOD5, N-NH3, lemak dan minyak (grease and oil), dan N-NO3. Pengambilan sampel kualitas air laut dilakukan secara langsung, Sampel air laut yang diperoleh kemudian dilakukan pengujian sesuai metode yang mengacu pada peraturan yang berlaku sesuai izin lingkungan no.02.85.12 tahun 2014. Sampel hasil analisis laboratorium dibandingkan dengan baku mutu sesuai Keputusan Menteri Lingkungan Hidup Nomor 51 Tahun 2004. Hasil analisis labolatorium kualitas air laut yaitu kekeruhan kisaran <0,40 – 0,60 NTU, TSS <1,6 – 3,6 mg/L, BOD5 9,3 – 11,1 mg/L, N-NH3 <0,03 mg/L, lemak dan minyak (grease dan oil) <0,2 mg/L, N-NO3 < 0,006 mg/L, suhu 31,2 – 31,7°C, serta pH 8,01 – 8,17. Kecenderungan tingkat kekritisan kualitas air laut di FSO Challenger yang fluktuatif mengakibatkan dampak terhadap kualitas air laut sekitar FSO Challenger. Pengawasan kualitas dari air laut di sekitar FSO Challenger dengan pengolahan air terproduksi yang di setting kembali di slope tank dan dialirkan ke separator, pengelolaan pada air pendingin dengan mengatur debit maksimum dan pengoperasian sistem secara kontinyu.ABSTRACTFloating Storage and Offloading (FSO) is located at coordinates 6° 43'51.84” South Latitude and 112° 09'19.84” East Longitude is in the Bawean Block. The FSO facility is a crude oil carrier and storage tanker with a capacity of 900,000 barrels. This study aims to (1) determine the parameters of sea water quality in FSO Challenger in the second semester of 2018 (2) find the potential and criticality of sea water quality in FSO Challenger in 2015-2018. The research location is in the Upstream and Downstream sections of the FSO Challenger, the parameters tested are turbidity, TSS, temperature, pH, BOD5, N-NH3, grease and oil (grease and oil), and N-NO3. Sampling of seawater quality is carried out directly. The seawater samples obtained are then tested based on methods that refer to applicable regulations according to environmental permits no. 02.85.12 of 2014. Samples from laboratory analysis are compared with quality standards according to Decree of the Minister of the Environment Number 51 of 2004. The results of laboratory analysis of sea water are turbidity in the range of <0.40 – 0.60 NTU, TSS <1.6 – 3.6 mg/L, BOD5 9.3 – 11.1 mg/L, N- NH3 <0.03 mg/L, fats and oils (grease and oil) <0.2 mg/L, N-NO3 < 0.006 mg/L, temperature 31.2 – 31.7°C, and pH 8.01 – 8.17. The level of criticality of sea water quality in FSO Challenger which fluctuates has an impact on sea water quality around FSO Challenger. Monitoring the quality of seawater around the Challenger FSO by treating the produced water which is set back in the slope tank and into the separator, managing the air conditioner by adjusting the maximum flowrate and operating the system continuously.
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Darusalam, Ucuk, Fitri Yuli Zulkifli, Purnomo Sidi Priambodo, and Eko Tjipto Rahardjo. "Hybrid optical communications for supporting the Palapa Ring network." Bulletin of Electrical Engineering and Informatics 9, no. 3 (June 1, 2020): 1055–66. http://dx.doi.org/10.11591/eei.v9i3.2008.

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In order to connecting villages in rural area with a city, a hybrid optical communication is proposed. The Optical fiber communications that are implemented as a backbone on the Palapa Ring network has an opportunity to be expanded to reach rural area through the implementation of free-space optical communications (FSO) as the optical relaying networks (ORN). The major problem of FSO as the ORN is turbulence effects induce an optical propagation. In this research, FSO as the ORN implements novel technique to improve the performance of hybrid FSO where the amplification of signal is produced through serial configuration of optical amplifiers in cascaded meanwhile to reduce the noise in the end of receiver, optical band pass filter is implemented. The simulation of hybrid FSO is performed in Optisystem 7.0 where ORN is implemented in two nodes. The length of optical fiber connection to FSO is set to be constant at 75 km. The range of optical propagation in FSO is set at 1–9.4 m. The results of simulation show that at the range of 1–8 Km of optical propagation under atmospheric turbulence, range values for SNR and BER are achieved at 46.23–26.61 dB and 6.7x10-17–1.5x10-6, respectively.
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Wu, Yan, Mengwan Jiang, Gang Li, and Dejin Kong. "Systematic Performance Analysis of Hybrid FSO/RF System over Generalized Fading Channels with Pointing Errors." Photonics 9, no. 11 (November 18, 2022): 873. http://dx.doi.org/10.3390/photonics9110873.

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Hybrid free space optical (FSO)/radio frequency (RF) system has attracted extensive attention because of its advantages of both the FSO and RF links. From the viewpoint of overall system performance, this paper presents a systematic analysis method of communication performance and security performance of the hybrid FSO/RF system with the Málaga turbulence channel and the α−μ fading channel. The hybrid FSO/RF system adopts the diversity method of maximum ratio combining (MRC) to receive signals. The new expressions of communication performance parameters (i.e., the bit error rate, the outage probability, the ergodic channel capacity) of the only FSO system and the hybrid system are obtained. Then, the new expressions of the security performance parameters (i.e., the security outage probability and the strictly positive secrecy capacity) of the hybrid system with the FSO or RF links eavesdropping are derived, respectively. Our derived analytical expressions present an efficient tool to investigate the impact of system parameters on the overall performance of the hybrid system, namely modulation scheme, turbulence intensity, pointing errors, target rate, and eavesdropper output signal-to-noise ratio. The simulation results show that compared with the only FSO system, the hybrid system can significantly improve the communication performance of the system; the communication performance of the hybrid system using coherent binary phase shift keying (CBPSK) modulation is obviously better than the other two modulation technologies; with the deterioration of atmospheric environment (increasing turbulence intensity and pointing errors), the communication performance and security performance of the hybrid system will decline; both RF link eavesdropping and FSO link eavesdropping have a greater impact on the security performance of the hybrid systems; whether it is FSO link eavesdropping or RF link eavesdropping, the reduction of target rate and output signal-to-noise ratio of the eavesdropper can improve the security performance of the hybrid system.
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Hagel, Corina, Bärbel Blaum, Thorsten Friedrich, and Johann Heider. "Characterisation of the redox centers of ethylbenzene dehydrogenase." JBIC Journal of Biological Inorganic Chemistry 27, no. 1 (November 29, 2021): 143–54. http://dx.doi.org/10.1007/s00775-021-01917-0.

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AbstractEthylbenzene dehydrogenase (EbDH), the initial enzyme of anaerobic ethylbenzene degradation from the beta-proteobacterium Aromatoleumaromaticum, is a soluble periplasmic molybdenum enzyme consisting of three subunits. It contains a Mo-bis-molybdopterin guanine dinucleotide (Mo-bis-MGD) cofactor and an 4Fe–4S cluster (FS0) in the α-subunit, three 4Fe–4S clusters (FS1 to FS3) and a 3Fe–4S cluster (FS4) in the β-subunit and a heme b cofactor in the γ-subunit. Ethylbenzene is hydroxylated by a water molecule in an oxygen-independent manner at the Mo-bis-MGD cofactor, which is reduced from the MoVI to the MoIV state in two subsequent one-electron steps. The electrons are then transferred via the Fe–S clusters to the heme b cofactor. In this report, we determine the midpoint redox potentials of the Mo-bis-MGD cofactor and FS1–FS4 by EPR spectroscopy, and that of the heme b cofactor by electrochemically induced redox difference spectroscopy. We obtained relatively high values of > 250 mV both for the MoVI–MoV redox couple and the heme b cofactor, whereas FS2 is only reduced at a very low redox potential, causing magnetic coupling with the neighboring FS1 and FS3. We compare the results with the data on related enzymes and interpret their significance for the function of EbDH. Graphical abstract
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Thakur, Er Sushila, and Er Rajeev Thakur. "A SURVEY ON PERFORMANCE OF FREE SPACE OPTICAL COMMUNICATION LINK." INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 14, no. 12 (August 24, 2015): 6295–303. http://dx.doi.org/10.24297/ijct.v14i12.1730.

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The modern era of communication needs a system with high bandwidth and high speed datarates.To fulfill rapid demands in today’s technology era, Free space optical (FSO) communication system has become very attractive technology, because they provides high bandwidth, license free spectrum using infrared beam, and are a reliable means of communications. The first part of the paper introduces the FSO system its block diagram and also the reason behind its usage. The second part informs about the factors which impairs the performance of the system. The third part will define the factors which enhance the performance of FSO system. The fourth part here will discuss which type of frequency is better for FSO system. The last part will describe about the different modulation techniques and which  modulation is good for FSO system.Â
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26

Park, Siwoong, Chan Il Yeo, Young Soon Heo, Ji Hyoung Ryu, Hyun Seo Kang, Dong-Seon Lee, and Jae-Hyung Jang. "Tracking Efficiency Improvement According to Incident Beam Size in QPD-Based PAT System for Common Path-Based Full-Duplex FSO Terminals." Sensors 22, no. 20 (October 13, 2022): 7770. http://dx.doi.org/10.3390/s22207770.

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Free space optical (FSO) communication can support various unmanned aerial vehicles’ (UAVs) applications that require large capacity data transmission. In order to perform FSO communication between two terminals, it is essential to employ a pointing, acquisition, and tracking (PAT) system with an efficient and optimal performance. We report on the development of a common optical-path-based FSO communication system, tailored for applications in UAVs. The proposed system is equipped with a quadrant photodiode (QPD)-based PAT system without an additional beacon beam subsystem. The presented approach reduced the structural complexity and improved the tracking efficiency for the same size, weight, and power (SWaP). To achieve a robust FSO link in a dynamic UAV environment, the observability and controllability were obtained based on the linearized control according to the incident beam size on the QPD, which was verified by optical simulation and experiments. As a result, the QPD-based PAT system for implementing FSO links demonstrated an up to 4.25 times faster tracking performance. Moreover, the FSO link experimentally confirmed the 1.25 Gbps full-duplex error-free communication at a 50 m distance.
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Shahiduzzaman, Kazi, Majumder F. Haider, and Bijoy K. Karmaker. "Terrestrial free space optical communications in Bangladesh: transmission channel characterization." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 4 (August 1, 2019): 3130. http://dx.doi.org/10.11591/ijece.v9i4.pp3130-3138.

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This research work focused on transmission channel characterization of Free-Space-Optical (FSO) communications technology for deploying in the developing country like Bangladesh. To meet the tremendous amount of data traffic, mobile operators and ISPs need better solution than the existing RF and fiber optic communications. Moreover, Bangladesh is entering in the era of satellite communications by launching its own satellite. So, Bangladesh needs such communication technology that provides higher channel bandwidth, sophisticated transmission security and can cope channel dispersion. FSO is a good candidate that can meet all these features. The transmission channel characterization plays a significant role in optimizing the performance of FSO link. In this work, the channel characterization of FSO technology from the weather perspective of Bangladesh has been investigated thoroughly. The obtained results show that the atmospheric scattering effect does not hamper the short range FSO link performance, whereas, the atmospheric turbulence effect is not favorable to deploy FSO technology with reasonable quality signal unless it is optimized properly using antenna aperture averaging technique.
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Gupta, Ritu, and Ankita Aggarwal. "Fog and Atmospheric Turbulence in FSO: Models to mitigate." CGC International Journal of Contemporary Technology and Research 2, no. 1 (December 30, 2019): 65–67. http://dx.doi.org/10.46860/cgcijctr.2019.12.20.65.

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Free space optics (FSO) is an attractive technique and provides reliability in comparison to radio frequency (RF). The FSO provides high data rate capability and has high bandwidth efficiency. The FSO provides various advantages to radio frequency and it is operable at rain also. But as other techniques FSO also has some issues like absorption, scintillation and scattering, which degrades the quality of the signal. There are various models which estimates the losses due to fog and absorption. In this paper we have analysed the kim, kruse and gamma gamma - gamma turbulence modelin terms of atmospheric attenuation or visibility
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Ghazi, Alaan, S. A. Aljunid, Awab Noori, Syed Zulkarnain Syed Idrus, C. B. M. Rashidi, and Aras Al-dawoodi. "Design & investigation of 10x10 gbit/s MDM over hybrid FSO link under different weather conditions and fiber to the home." Bulletin of Electrical Engineering and Informatics 8, no. 1 (March 1, 2019): 121–26. http://dx.doi.org/10.11591/eei.v8i1.1398.

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In this paper, we design and investigate 10-channels of mode division multiplexer (MDM) over hybrid free-space optics (FSO) link in several weather conditions to achieve the maximum possible medium range and fiber to the home (FTTH) for high bandwidth access networks. System capacity can be effectively increased with the use of MDM over hybrid FSO-FTTH. In this study, a 10-channel MDM over FSO-FTTH system has been analyzed in different weather conditions that operate at 1550 nm wavelength. The simulated system has transmitted 100 Gbit/s up for a distance of 3200 meters FSO in superbly clear weather condition. It also transmitted 100 Gbit/s up for a distance of 650 meters FSO during heavy rain. The validation of this study is measures based on eye diagrams bit-error rates (BER) that have been analyzed.
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30

Kiralan, M., G. Çalik, S. Kiralan, A. Özaydin, G. Özkan, and M. F. Ramadan. "Stability and volatile oxidation compounds of grape seed, flax seed and black cumin seed cold-pressed oils as affected by thermal oxidation." Grasas y Aceites 70, no. 1 (January 28, 2019): 295. http://dx.doi.org/10.3989/gya.0570181.

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The old-pressed oils (CPO) from grape seeds (GSO), flax seeds (FSO) and black cumin seeds (BSO) were analyzed for their fatty acid profiles, tocopherols, total phenolics, bioactives and phenolic compositions. The stability of CPO under thermal oxidation conditions was evaluated. The main fatty acid in FSO was linolenic acid (56.5% of total fatty acids); while GSO and BSO were rich in linoleic acid, which accounted for 66.8 and 56.8%, respectively. GSO was rich in ?-tocopherol (123.0 mg/kg), while ?-tocopherol was a prevalent isomer in FSO and BSO (137.9 and 128.9 mg/kg, respectively). The total phenolic contents in the oils ranged from 554 mg GAE/kg oil (FSO) to 1140 mg GAE/kg oil (BSO). Luteolin, dihydroquercetin and benzoic acids were the dominant bioactives and phenolics in FSO, GSO and BSO, respectively. Based on the oxidative stability index (OSI) value, BSO showed the highest value (6.14 h) among the other oils. The oxidative stability of FSO and BSO were higher than GSO according to peroxide value (PV) and conjugated diene (CD) values of the oils during storage at 60 °C. Hexanal, 2,4-heptadienal and (E,E)-2,4-heptadienal were the major volatile oxidation compounds (VOC) in FSO. Hexanal and (E)-2-heptanal were the main identified VOC in the GSO and BSO under the same oxidation conditions.
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31

Ali, Mustafa H., Rehab I. Ajel, and Samira Abdul-kader Hussain. "Performance analysis of beam divergence propagation through rainwater and snow pack in free space optical communication." Bulletin of Electrical Engineering and Informatics 10, no. 3 (June 1, 2021): 1395–404. http://dx.doi.org/10.11591/eei.v10i3.2857.

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In the present work the future communication requirements need to fulfill with high data rate, FSO (free space optic) with it is tremendous potential is the solution. This research observed the effectiveness analysis of FSO systems by modifying one of the most important FSO parameters beam divergence, under the most affected weather attenuating condition Rainwater and snow pack. The simulation is obtained and analyzed under single channels CSRZ-FSO (carrier-suppressed return-to-zero/free space optical) systems having capacity of 40 Gbps between two transceivers with variable distance. The connection is presently under 5 meteorological turbulences (light rain, medium rain, wet snow, heavy rain and dry snow). The results show the heavy rain and dry snow have a very high attenuation carried out in terms of Q-factor. this result led us to conclude that small divergence offers significant performance improvement for FSO link and this performance decrease every time the beam divergence increase, Therefore, to build inexpensive and reliable transmission media, we go with new method that still in the experiment area called hybrid RF/FSO (radio frequency/free space optical) that compatible with atmospherically status.
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32

Hsu, Ching-Hsuan, Syu-Yang Jiang, Shang-En Hsieh, Chien-Hung Yeh, Yu-Ting Lai, Lan-Yin Chen, Shien-Kuei Liaw, and Chi-Wai Chow. "Hybrid Self-Protected Fiber-FSO WDM-PON System with Fiber Breakage Prevention." Photonics 9, no. 11 (November 2, 2022): 822. http://dx.doi.org/10.3390/photonics9110822.

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In this research, we present and design a blended wavelength-division-multiplexing passive optical network (WDM-PON) architecture to deliver both baseband and free-space optical (FSO) signals by using two wavelength bands over an available bandwidth to avoid the signal interference. Only using few additional components in the optical line termination (OLT) and optical network unit (ONU)/optical wireless unit (OWU) can achieve self-protected operation in the presented hybrid fiber-FSO access network against fiber breakage. In the measurement, eight WDM wavelengths with 24.3 Gbit/s on-off keying (OOK) modulation format are applied to verify and discuss the bit error rate (BER) performances of baseband and FSO signals, respectively, through 25 km fiber and 2 m wireless FSO connections. Therefore, the presented PON not only can deliver both baseband and FSO traffics, but can also provide a self-restored mechanism against fiber fault.
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33

Chauhan, Isha, and Manav R. Bhatnagar. "Performance of Transmit Aperture Selection to Mitigate Jamming." Applied Sciences 12, no. 4 (February 21, 2022): 2228. http://dx.doi.org/10.3390/app12042228.

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In this work, we investigate the impact of the transmit aperture selection technique to alleviate the effect of jamming on a free space optical (FSO) communication system. We consider the FSO system to suffer from a jamming signal and Gaussian noise concurrently. The analysis in this paper is conducted on the assumption that all wireless optical links follow the negative exponential distribution with pointing error. A general N×1 FSO system is studied, which allows the transmitter to select a link with the maximum channel gain to transmit the information. We derive a closed-form expression of the bit error rate (BER) of the considered FSO system in the presence of a jammer. We extract the analytical coding gain and diversity order from the asymptotic behavior of the derived BER. We show that the transmit aperture selection allows the FSO system corrupted by a jammer to attain a diversity order of 0.5 N, equal to that of a multiple-input single-output FSO system, while appreciably reducing the power requirements of (N − 1) transmitters. The theoretical analysis is verified by simulations. We also make a quantitative comparison with repetitive coding (RC) and optical space shift keying (OSSK) and show that the transmit aperture selection has a 3 dB advantage over RC; moreover, for a 2×1 system, it provides twice the diversity offered by OSSK. The tenacity of aperture selection is also studied numerically for Gamma-Gamma fading FSO channels.
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HALUŠKA, Renát, and Ľuboš OVSENÍK. "EXAMPLE OF SWITCHING HYBRID FSO/RF SYSTEMS." Acta Electrotechnica et Informatica 20, no. 4 (January 21, 2021): 27–31. http://dx.doi.org/10.15546/aeei-2020-0022.

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This article addresses the issue of optical communication with Free Space Optics (FSO) and its use. The article deals with the design and construction of a monitoring system designed for the collection and processing of data characterizing the nature of conditions along the transmission path of a hybrid FSO system with a radio communication link. Due to the vulnerability of the FSO transmission channel to weather conditions, it is necessary to predict the strength of the received signal and switch to a backup line based on machine learning using decision trees.
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Blazhennyi, Nazarii, Oleksandr Turovsky, Liudmyla Kyrpach, Yana Kremenetskaya, and Olena Zhukova. "Development of methods for the assessment of vulnerability of the receiver input of free-space optical communication from the effects of radiation, as the effects of the destruction of radiation hazardous objects." ScienceRise, no. 3 (June 30, 2021): 21–28. http://dx.doi.org/10.21303/2313-8416.2021.001919.

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Object of research: Free-space optical communication (FSO). Investigated problem: Significant advantages of free-space optical communication in comparison with the existing networks of useful data transmission justify their use in various complex environmental conditions, which require the organization of fast and reliable digital communication when it is impossible or limitation to use wired or radio lines. Main scientific results: One of the factors that can considerably affect the FSO efficiency is radioactive radiation produced by various sources and phenomena of ionizing effects. In the research the issues of the assessment of the vulnerability of the FSO receivers of input signal from the effects of gamma radiation are directly considered. The analysis of the design of the receiving path of the input signal of FSO is conducted and the list and the partial attenuation coefficients of radioactive radiation by the FSO components that separate the receiver of input signal from the external environment are determined. The area of practical use of research results: The methods has been developed and with its help the assessment of the vulnerability of the FSO receivers of input signal from the effects of gamma radiation, as the effects of the destruction of the radiation-hazardous object has been conducted. Innovative technological product: The nature of the influence of gamma radiation as the effects of the destruction of the radiation-hazardous object on the FSO receiver of input signal is determined. Scope of application of an innovative technological product: The results allow to develop a set of measures aimed at reducing the effects of gamma radiation, as the effects of the destruction of the radiation-hazardous object, on the FSO efficiency.
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36

WAHIDIN, Dasep, and Kai P. PURNHAGEN. "Determining a Science-based Food Safety Objective/Appropriate Level of Protection for Application in Developing Countries." European Journal of Risk Regulation 8, no. 2 (June 2017): 403–13. http://dx.doi.org/10.1017/err.2017.18.

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AbstractWhen determining the Appropriate Level of Protection (ALOP) in food safety law, developed countries rely on the Food Safety Objective (FSO) to meet the requirements of World Trade Organization (WTO) law and to provide a high level of protection based on insights from food safety science. Implementing an FSO/ALOP is resource-intensive and costly. Developing countries who would like to provide similar levels of protection are restricted by limited resources and often face difficulties implementing such an FSO-based ALOP. As a consequence, developing countries may base their ALOP on other legally acceptable reasons, which are non-scientific and less effective. We illustrate a less resource-intensive way to implement the FSO in the ALOP, which enables developing countries to design an ALOP that is based on food safety science. Depending on the resources available in the respective country, we map different possibilities to determine a science-based FSO/ALOP concept for developing countries, which also takes into account the requirements of WTO law.
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Maharjan, Nilesh, Nikesh Devkota, and Byung Wook Kim. "Atmospheric Effects on Satellite–Ground Free Space Uplink and Downlink Optical Transmissions." Applied Sciences 12, no. 21 (October 28, 2022): 10944. http://dx.doi.org/10.3390/app122110944.

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Free space optical (FSO) communications have the potential to be one of the most essential technologies for solving the high-bandwidth demands of communications between satellites and ground stations. In this study, we examine the impact of the atmosphere on satellite–ground FSO uplink and downlink communications. To consider diverse atmospheric conditions on both uplink and downlink, we derive FSO channel elements such as the fog attenuation coefficient, refractive index parameter, coherence length, turbulence model, and angle-of-arrival fluctuation. Unlike conventional work, we provide FSO channel analysis based on variations in the Fried parameter, zenith angle, scintillation index, and Rytov variance. Using simulation results from the optical settings, we examine the influence on channel performance of conditions such as atmospheric attenuation and intensity fluctuation. Based on this examination, we determine that 1550 nm is the preferred wavelength for both uplink and downlink FSO channels to mitigate the impact of turbulence and that larger receiver apertures lessen angle-of-arrival changes.
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38

Mikołajczyk, Janusz, Zbigniew Bielecki, Maciej Bugajski, Józef Piotrowski, Jacek Wojtas, Waldemar Gawron, Dariusz Szabra, and Artur Prokopiuk. "Analysis of Free-Space Optics Development." Metrology and Measurement Systems 24, no. 4 (December 20, 2017): 653–74. http://dx.doi.org/10.1515/mms-2017-0060.

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AbstractThe article presents state of work in technology of free-space optical communications (Free Space Optics − FSO). Both commercially available optical data links and their further development are described. The main elements and operation limiting factors of FSO systems have been identified. Additionally, analyses of FSO/RF hybrid systems application are included. The main aspects of LasBITer project related to such hybrid technology for security and defence applications are presented.
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39

Sultana, Maliha, Agnila Barua, Jobaida Akhtar, and Mohammad Istiaque Reja. "Performance Investigation of OFDM-FSO System under Diverse Weather Conditions of Bangladesh." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 5 (October 1, 2018): 3722. http://dx.doi.org/10.11591/ijece.v8i5.pp3722-3731.

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Free space optical (FSO) communication systems which are deployed for last mile access, being considered as a suitable alternative technology for optical fiber networks. It is one of the emerging technologies for broadband wireless connectivity which has also been receiving growing attention due to high data rate transmission capability with low installation cost and license free spectrum. However, the widespread use of FSO technology has been hampered by the randomly time varying characteristics of propagation path mainly due to atmospheric turbulence, sensitivity to diverse weather conditions and the nonlinear responsivity of laser diode. This paper presents the performance investigation of an OFDM-FSO system over atmospheric turbulence channels under diverse weather conditions of Bangladesh. The channel is modeled with gamma-gamma distribution using 16-QAM modulation format and 4×4 multiple transceiver FSO system. All possible challenges are imposed on the system performance such as atmospheric attenuation, turbulence, pointing error, geometric loss etc. The refractive index structure parameter and atmospheric attenuation coefficient for different weather conditions are calculated by using the data, collected from Bangladesh Meteorological Department. The acquired results can be fruitful for scheming, forecasting and assessing the OFDM-FSO system’s ability to transmit wireless services over turbulent FSO links under actual conditions of Bangladesh.
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40

Aboelala, Omar, It Ee Lee, and Gwo Chin Chung. "A Survey of Hybrid Free Space Optics (FSO) Communication Networks to Achieve 5G Connectivity for Backhauling." Entropy 24, no. 11 (October 31, 2022): 1573. http://dx.doi.org/10.3390/e24111573.

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Increased capacity, higher data rate, decreased latency, and better service quality are examples of the primary objectives or needs that must be catered to in the near future, i.e., fifth-generation (5G) and beyond. To fulfil these needs, cellular network design must be drastically improved. The 5G cellular network design, huge multiple-input multiple-output (MIMO) technology, and device-to-device communication are all highlighted in this comprehensive study. Hence, free-space optics (FSO) is a promising solution to address this field. However, FSO standalone is insufficient during turbulent weather conditions. FSO systems possess some limitations, such as being able to be disturbed by any interference between sender and receiver such as a flying bird and a tree, as it requires line-of-sight (LOS) connectivity. Moreover, it is sensitive to weather conditions; the FSO performance significantly decreases in bad weather conditions such as fog and snow; those factors deteriorate the performance of FSO. This paper conducts a systematic survey on the existing projects in the same area of research such as the hybrid FSO/Radio frequency (RF) communication system by listing each technique used for each model to achieve optimum performance in terms of data rate and Bit Error Rate (BER) to be implemented in 5G networks.
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41

Chauhan, Sonali, Rajan Miglani, Lavish Kansal, Gurjot Singh Gaba, and Mehedi Masud. "Performance Analysis and Enhancement of Free Space Optical Links for Developing State-of-the-Art Smart City Framework." Photonics 7, no. 4 (December 16, 2020): 132. http://dx.doi.org/10.3390/photonics7040132.

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In this paper, we have investigated and reported the performance of free-space optical (FSO) links operating in adverse atmospheric conditions. Since FSO links share operational similarity with fiber communication; hence, we believe that a cost-effective FSO framework can play a significant role in the transparent integration of high-speed network access backbones with the end-users. Different modulation formats, complemented with spatial diversity techniques, are discussed in this paper to strategize performance optimization of FSO links. Using bit error rate (BER) and signal-to-noise ratio (SNR) as performance metrics, it was found that binary phase-shift keying (BPSK) qualifies as the best technique modulation technique delivering SNR gain of 10 dB over on–off keying (OOK) operating link under similar channel conditions. Further performance optimization was achieved using space diversity reception wherein SNR witnessed a gain of 3 dB gain over the single-channel FSO link. In terms of application, the proposed model can help in developing a citizen-centric smart city ecosystem that can support seamless communication between heterogeneous smart devices.
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42

Alsharari, Meshari, Khaled Aliqab, Farman Ali, and Ammar Armghan. "Integrated Free-Space Optics and Fiber Optic Network Performance Enhancement for Sustaining 5G High Capacity Communications." International Journal of Optics 2023 (January 13, 2023): 1–9. http://dx.doi.org/10.1155/2023/8685686.

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In this paper, the integrated free-space optics (FSO) and fiber optic model is evaluated using new radio (NR) sub-THz link to sustain next generation 5G capacity. The proposed integrated model effectively applies over 25 km single mode fiber, 0.5 m RF wireless, and 500 m optical wireless. In addition, four different sub-THz frequencies (125, 150, 175, and 200 GHz) are estimated on NR-based 5G FSO network, including 22 Gbps 64quadrature amplitude modulation-orthogonal frequency division multiplexing (64QAM-OFDM) signal speed. The proposed FSO enabled fiber optic system is also measured mathematically to satisfy the data transmission accuracy. For confirmation, the theoretical approach of the presented FSO and fiber optic network is realized with an aggregate 342 Gbps speed 16 × 22 . The performance metrics comprising forward error limit (FEL), bit error rate (BER), and error vector magnitude (EVM) are used for weighing simulation results. The outlets of an integrated fiber-FSO network show that by applying NR 5G sub-THz, a high data rate with multiple inputs and multiple outputs (MIMO) transmission capacity can be adjusted victoriously.
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43

Qiong, Yan Guo, and Zhou Mao Hua. "Implementation of QC-LDPC Decoder Based on FPGA for FSO System." Applied Mechanics and Materials 668-669 (October 2014): 1269–72. http://dx.doi.org/10.4028/www.scientific.net/amm.668-669.1269.

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QC-LDPC can bring a higher coding gain to the FSO system, but the complexity of the decoding algorithm restricted its application in high-speed FSO system.In this paper, it adopts an improved Modified Min-sum Algorithm (MMSA) to reduce the decoding complexity and save decoding time. In this paper, the author programs the decoder with VHDL Hardware Description Language and analyzes the static time of the design with Synplify Pro and QuartusII to verify the correctness. Moreover, each functional unit is downloaded to the EP3C16Q240C8 chip produced by ALTERA Company and encapsulated into the IP core. Finally, we used MATLAB software to build the FSO system for testing decoder performance. The results show that the QC-LDPC decoder based on FPGA has higher reliability in FSO system.
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44

Mikołajczyk, Janusz. "An Overview of Free Space Optics with Quantum Cascade Lasers." International Journal of Electronics and Telecommunications 60, no. 3 (October 28, 2014): 259–64. http://dx.doi.org/10.2478/eletel-2014-0033.

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Abstract The article presents an overview of the work on quantum cascade lasers application in free space optical systems (Free Space Optics - FSO). There are discussed the main issues of the open-space laser communications and their practical construction. Comparative analyses of each FSO technology were performed. Brief description of quantum cascade (QC) lasers and some developments related to the use of these lasers in optical data link are also presented. In summary, the constructed models of FSO links with QC lasers are characterized.
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Sahota, Jasjot Kaur, and Divya Dhawan. "Performance Analysis of Homodyne-Based FSO System Using Various Optical Amplifiers." Journal of Optical Communications 41, no. 4 (April 28, 2020): 339–46. http://dx.doi.org/10.1515/joc-2018-0005.

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AbstractA detailed performance analysis of homodyne-based coherent detection in Free-space optics (FSO) with various optical amplifiers is presented in this paper. Using homodyne detection in FSO system, the effect of scintillation is mitigated. To further enhance the performance of FSO system, various optical amplifiers such as erbium-doped fibre amplifier, semiconductor optical amplifier, gain-controlled amplifier and black box model of amplifier can be employed in the system. Improvement in the system can be validated in terms of BER, Q-factor and eye diagram.
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46

Álvarez-Roa, Carmen, María Álvarez-Roa, Francisco J. Martín-Vega, Miguel Castillo-Vázquez, Thiago Raddo, and Antonio Jurado-Navas. "Performance Analysis of a Vertical FSO Link with Energy Harvesting Strategy." Sensors 22, no. 15 (July 29, 2022): 5684. http://dx.doi.org/10.3390/s22155684.

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In this paper we investigate the application of free space optical (FSO) communications, energy harvesting, and unmanned aerial vehicles (UAVs) as key technology enablers of a cost-efficient backhaul/fronthaul framework for 5G and beyond (5G+) networks. This novel approach is motivated by several facts. First, the UAVs, acting as relay nodes, represent an easy-to-deploy and adaptive network that can provide line-of-sight between the base stations and the gateways connected to the core network. Second, FSO communications offer high data rates between the UAVs and the network nodes, while avoiding any potential interference with the 5G radio access networks. Third, energy harvesting in the optical domain has the potential to extend the UAVs’ battery life. Nevertheless, the presence of atmospheric turbulence, atmospheric attenuation, and pointing errors in the FSO links severely degrades their performance. For this reason an accurate yet tractable modelling framework is required to fully understand whether an UAV-FSO backhaul/fronthaul network with energy harvesting can be applied. To this end, we consider a composite channel attenuation model that includes the effect of turbulence fading, pointing errors, and atmospheric attenuation. Using this model, we derive analytical closed-form expressions of the average harvested energy as a function of the FSO link parameters. These expressions can be used to improve energy harvesting efficiency in FSO link design. We have applied our proposed expressions to evaluate the energy harvested in vertical FSO links for a variety of real scenarios under a modified on-off keying (OOK) scheme optimized for energy harvesting. From the simulations carried out in this paper, we demonstrate that significant values of harvested energy can be obtained. Such performance enhancement can complement the existing deployment charging stations.
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47

FIORENTIN, Eliana, Anderson TIECHER, Cristina MENEGAT, Clarice SOARES, Adelina AIRES, Ricardo ROCHA, and Felix Hilario Diaz GONZALEZ. "Accuracy of two hand-held electronic devices for determination of blood β-hydroxybutyrate in dairy cows." Revista Brasileira de Saúde e Produção Animal 18, no. 3 (July 2017): 439–45. http://dx.doi.org/10.1590/s1519-99402017000300004.

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SUMMARY The cowside determination of blood β-hydroxybutyrate (BHB) is an important tool for diagnosing subclinical ketosis in dairy cattle. Portable methods to measure BHB have been introduced in the past years. This study evaluated the accuracy of two hand-held electronic devices for blood determination of BHB in dairy cows at early postpartum. A total of 98 blood samples were collected from dairy cows in the first month of lactation and tested with FreeStyle Optium (FSO, Abbott) and KetoVet (KVE, TaiDoc) portable devices according to the manufacturer instructions. Spectrophotometric BHB analysis (Ranbut, Randox) was used as standard method. The incidence of subclinical ketosis was 37.7 % determined by the standard method, 40.8 % determined by the FSO system and 42.8 % detected with the KVE system. The sensitivity and specificity indexes were 88.1% and 98.4% for FSO and 78.7% and 92.4% for KVE, respectively. The Pearson´s correlation coefficients comparing the portable devices to the standard technique were 0.96 for FSO and 0.93 for KVE. No significant difference in BHB values was found between the two portable tests and the standard method. Predictive values (PV) were better using FSO (positive PV 97.3 %, negative PV 92.4%) than using KVE (positive PV 88.1 %, negative PV 85.9 %). Passing-Bablok regressions revealed good agreement between methods. Though FSO system had a better performance than KVE system, the results suggest that the two portable systems have good accuracy and are reliable for measuring BHB.
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48

Mohamed Hadi Habaebi, N.F.A Jamal, Md. Rafiqul Islam, and Ahmed Basahel. "Tropical Terrestrial Free Space Optical Link Performance Analysis." International Journal of Interactive Mobile Technologies (iJIM) 16, no. 12 (June 21, 2022): 94–102. http://dx.doi.org/10.3991/ijim.v16i12.30119.

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Free Space Optical (FSO) has a very good potential alternative solution to Radio Frequency (RF) to provide high terrestrial wireless communication. In tropical region, the only drawback of FSO is atmospheric attenuation due to mainly haze and rain. This study investigates the performance of FSO system over link distances that ranges between 9 km to 12 km as the average visibility in Kuala Lumpur, Malaysia is 10 km. Two models used to predict the atmospheric attenuation, namely Kruse model and modified Kruse model. These models are valid to predict the haze attenuation for visibilities that range between 9 to 12 km. The modified/corrected Kruse model shows some limitations in the prediction of haze attenuation over longer wavelength. However, the study indicates that attenuation due to haze is low, while air quality in Kuala Lumpur, Malaysia is acceptable. As the size of haze particles varies from 0.01 to 1 µm, the longer wavelength is preferable as 1550 nm to enhance FSO performance compared to 850 nm and 600 nm wavelengths. Thus, the longer wavelength is the optimal choice to enhance the FSO performance as it caused low scattering.
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49

Cao, Yang, Huaijun Qin, Xiaofeng Peng, Yuhan Wang, and Zupeng Zhang. "Research on Polarization Coding Cooperative Communication Scheme for FSO System." Electronics 11, no. 10 (May 17, 2022): 1597. http://dx.doi.org/10.3390/electronics11101597.

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To solve the problems of interruption events and the high bit-error rate of the FSO system caused by atmospheric turbulence, an FSO cooperative communication scheme based on system polarization code is proposed. In this scheme, the upper limit of the average bit-error rate of the atmospheric turbulence channel is used to construct the frozen bit set of the system polarization code, and the information bit set of the S−R link is recovered by using the ownership relationship between the frozen bit set of the S−R link and the S−D link at the destination node. Finally, the information bits of the S−R link and S−D link are combined using equal gain combination, and the original information is recovered by decoding. The simulation results show that the FSO cooperative communication system can overcome the influence of atmospheric turbulence and improve the system performance, and the bit-error rate performance of the FSO cooperative communication system can be improved by at least 0.5dB; the outage probability of the FSO cooperative communication system can be reduced to less than 10−7, and it shows a stable inhibitory effect on strong turbulence conditions.
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Wu, Yan, Jing Chen, Jianzhong Guo, Gang Li, and Dejin Kong. "Performance Analysis of a Multi-Hop Parallel Hybrid FSO/RF System over a Gamma–Gamma Turbulence Channel with Pointing Errors and a Nakagami-m Fading Channel." Photonics 9, no. 9 (September 2, 2022): 631. http://dx.doi.org/10.3390/photonics9090631.

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Due to the influence of the atmospheric environment and pointing errors, the performance of free space optical communication is greatly limited. In this paper, we propose a parallel multi-hop hybrid free space optical (FSO)/radio frequency (RF) system to improve the system performance. The FSO sub-link and RF sub-link are modeled by Gamma–Gamma turbulence with pointing errors and Nakagami-m distributions, respectively. Based on the selective combination scheme, the probability density function (PDF) and cumulative distribution function (CDF) of the output signal-to-noise ratio (SNR) of the hybrid FSO/RF one-hop or direct link are obtained. Then, the PDF and CDF of the output SNR of the parallel multi-hop hybrid system are derived with the decoded forward (DF) protocol considered. Finally, the expressions of the average bit error rate (ABER) and outage probability are derived for the parallel multi-hop hybrid system, the hybrid FSO/RF direct link, and the FSO-only direct link. The results show that the parallel multi-hop hybrid system can effectively mitigate the negative impact of atmospheric turbulence and pointing errors and can significantly improve the system performance.
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