Adjacent Satellite Research Articles

Analysis of the lithospheric magnetic anomalies and tectonics in continental China and the adjacent regions using CHAMP satellite data

In this paper, the CHAMP satellite data from the last decade are used to map the lithospheric magnetic field in continental China at altitudes of 300 and 400 km using the spline function model technique. The results show that our model has higher amplitude than the spherical harmonic magnetic field model MF7. The resulting lithospheric anomaly distribution of continental China agrees with the geotectonic structure and crustal thermal structure. The magnetic anomaly distribution clearly indicates extrusion of the Tibetan Plateau towards the northeast and northwest directions. Northward movement is impeded by the relative rigid Tarim Basin featured with positive magnetic anomalies. The positive magnetic anomalies in Tarim basin extend to the northern Tibetan Plateau, suggesting that the southern part of Tarim Basin underthrusted the northern Tibetan Plateau.

Experiences from Large-Scale Forest Mapping of Sweden Using TanDEM-X Data

This paper report experiences from the processing and mosaicking of 518 TanDEM-X image pairs covering the entirety of Sweden, with two single map products of above-ground biomass (AGB) and forest stem volume (VOL), both with 10 m resolution. The main objective was to explore the possibilities and overcome the challenges related to forest mapping extending a large number of adjacent satellite scenes. Hence, numerous examples are presented to illustrate challenges and possible solutions. To derive the forest maps, the observables backscatter, interferometric phase height and interferometric coherence, obtained from TanDEM-X, were evaluated using empirical robust linear regression models with reference data extracted from 2288 national forest inventory plots with a 10 m radius. The interferometric phase height was the single most important observable, to predict AGB and VOL. The mosaics were evaluated on different datasets with field-inventoried stands across Sweden. The root mean square error (RMSE) was about 21%–25% (27–30 tons/ha and 52–65 m3/ha) at the stand level. It was noted that the most influencing factors on the observables in this study were local temperature and geolocation errors that were challenging to robustly compensate against. Because of this variability at the scene-level, determinations of AGB and VOL for single stands are recommended to be used with care, as an equivalent accuracy is difficult to achieve for all different scenes, with varying acquisition conditions. Still, for the evaluated stands, the mosaics were of sufficient accuracy to be used for forest management at the stand level.

An ASI Suppression Scheme Based on Array Synthesis

An adjacent satellite interference (ASI) suppression scheme based on transmitting antennas array synthesis is proposed in this paper. The scheme ensures the ASI under the upper bound specified by international regulations, and simultaneously maximize the main-axis radiated power. Specifically, the interference suppression problem is converted into a uniform linear array (ULA) synthesis problem, and then solved by two algorithms. Numerical results are presented to illustrate the performance of the scheme.

Subclonal analysis in a lobular breast cancer with classical and solid growth pattern mimicking a solid-papillary carcinoma.

Recently, a new variant of invasive lobular breast cancer (ILBC) with solid‐papillary‐like growth pattern has been described. We present a case of ILBC with solid‐papillary‐like growth pattern in the main tumour mass and classical invasive lobular growth pattern in adjacent satellite foci. The two tumour components were subjected to comprehensive molecular analyses. Both components were ER/PR‐positive, HER2‐negative, and showed a complete loss of E‐cadherin and beta‐catenin protein expression, as determined by immunohistochemistry. Gene expression profiling classified the main tumour and a satellite focus as luminal‐B and luminal‐A subtypes, respectively. Whole‐genome copy number profiles were highly similar in both tumour components. Shared copy number alterations (CNAs) included gains of chromosome 1q21.1–q43 and losses of chromosome 16q11.2–q24.3, the locus of the CDH1/E‐cadherin tumour suppressor gene. CNAs detected only in the main tumour included a gain of chromosome 20q12–q13.33 and a loss of chromosome 1p36.33–p34.3, which has recently been associated with the solid variant of ILBC. Next generation sequencing revealed an identical, truncating CDH1 mutation (p.G169fs*5) in both tumour components confirming a common clonal ancestry. In conclusion, we confirm the recently described variant of ILBC with solid‐papillary‐like growth pattern and provide evidence that it evolves from classical ILBC by subclonal evolution.

Role of Chemiluminescence examination as non-invasive diagnostic tool in early detection of Leukoplakia

ObjectivesTo assess the efficacy of Chemiluminescent light (Vizilite plus) in enhancing visualization and its ability to highlight Leukoplakia lesion. Material and methodsThis was a cross-sectional study done on 40 study subjects. Subjects were inducted into the study irrespective of age and sex based on the specific inclusion and exclusion criteria. The lesion parameters like the location of the lesion, the shape of lesion, the size, the extent, borders and the presence or absence of any adjacent satellite lesions were assessed under Incandescent light followed by Toluidine blue and Vizilite plus examinations. Histopathological examination results were considered as the gold standard and TBLU and CHEM outcomes were compared to them. ResultsVizilite plus examination method was most effective in assessing the size, borders and shape of the lesions followed by Toluidine blue and Incandescent light examinations. Toluidine blue and Vizilite plus examination methods demonstrated the sensitivity of 100% and specificity of 97.3%. They also demonstrated PPV of 100% and NPV of 75% with reliable accuracy of 97.5%. ConclusionChemiluminescent light is a stepping stone and has the potential to revolutionize the diagnostic protocol for patients with potentially premalignant lesions. The device can be used as a general oral mucosal examination system and may in particular improve the visualization of potentially premalignant lesions.

Underdetermined blind source separation of adjacent satellite interference based on sparseness

The problem of underdetermined blind source separation of adjacent satellite interference is proposed in this paper. Density Clustering algorithm (DC-algorithm) presented in this article is different from traditional methods. Sparseness representation has been applied in underdetermined blind signal source separation. However, some difficulties have not been considered, such as the number of sources is unknown or the mixed matrix is ill-conditioned. In order to find out the number of the mixed signals, Short Time Fourier Transform (STFT) is employed to segment received mixtures. Then, we formulate the blind source signal as cluster problem. Furthermore, we construct Cost Function Pair (ρ, δ) and Decision Coordinate System by using density clustering. At the end of this paper, we discuss the performance of the proposed method and verify the novel method based on several simulations. We verify the proposed method on numerical experiments with real signal transmission, which demonstrates the validity of the proposed method.

Merkel Cell Carcinoma.

Merkel cell carcinoma is a primary neuroendocrine tumour of the skin arising from the dermis and extending into the subcutis, occurring commonly in sun-exposed areas of the head and neck of the elderly. Clinically, non-specific erythematous or violaceous firm nodules or small plaques which may be surrounded by small adjacent satellite tumours are seen. Diagnosis of Merkel cell carcinoma is difficult by light microscopy alone and need of ancillary techniques like electron microscopy and immunohistochemistry may be necessary. Treatment modalities are dependent on the stage of the disease. We report a 73-year-old male who presented with multiple nodular swellings on the right buttock, right side of the lower abdomen, and right upper thigh since 2months. Biopsy revealed Merkel cell carcinoma and immunohistochemistry confirmed it. In order to stage the disease, an ultrasound abdomen was done which showed multiple enlarged para-aortic lymph nodes and retroperitoneal lymph nodes with necrotic centres and right-sided hydroureteronephrosis and computed tomography is advised for further co-relation. Computed tomography of the abdomen showed extensive lymphadenopathy with perinodal fat forming conglomerate masses in the para-aortic, aortocaval, retrocaval, bilateral iliac, and inguinal region encasing the aorta, vena cava, and bilateral iliac arteries; extensive soft tissue density nodules in the skin extending into the subcutaneous plane and superficial muscular plane of the gluteal region and lower abdomen; and mild hydronephrosis of the right kidney due to encasement of lower ureter by lymphadenopathy. We report a case of Merkel cell carcinoma with distant metastases with the same relevant discussion.

Imaging and enhancement characteristics of coccidioidomycosis nodules assessed by dynamic contrast-enhanced computed tomography

ObjectiveTo describe the dynamic contrast-enhanced CT (DCECT) appearance of pulmonary nodules related to infection with coccidioidomycosis. MethodsRetrospective review of a database of DCECTs identified a subset of patients with pulmonary nodules related to coccidioidomycosis. General and DCECT imaging characteristics of these nodules were evaluated. Results16 of the 44 nodules identified (36.4%) showed enhancement on DCECT imaging. The majority (74.9%) of enhancing nodules demonstrate delayed (3 or 4 min) peak enhancement. The majority (88.6%) of the 44 nodules were either smooth or lobulated in appearance. Only 1 (2.3%) of the nodules was cavitary. 19 (43.2%) of the nodules had adjacent satellite nodules. DCECT can be a useful study to help characterize pulmonary nodules in areas with endemic Coccidioides with an expected false-positive rate of ∼30–40%. Biopsy could potentially be averted in 60–70% of nodules by evaluating with DCECT prior to tissue sampling. ConclusionWhen combined with morphological, serological, clinical, and historical information DCECT can be a powerful tool for reducing the number of benign nodules being biopsied and/or resected.

Underdetermined blind separation of adjacent satellite interference in modern satellite communication systems

Underdetermined blind separation of adjacent satellite interference in modern satellite communication systems

Performance Analysis of Correlated Handover Service in LEO Mobile Satellite Systems

Analytical models for low earth orbit mobile satellite systems (LEO-MSSs) should consider service time correlation in adjacent satellite spot beams. This letter presents a simple analytical framework for the efficient performance evaluation of new and handover services in LEO-MSSs with correlated service times. When the fading channel is temporally correlated, channel characteristics in the preceding and succeeding spot beams do not change dramatically, especially for services with short transmission times. A closed-form solution of the correlated queue service time is derived using probability generating functions whose moments are used to derive the blocking probabilities of handover and new services. The system is then modeled as a queuing system with correlated service time and its performance investigated.

Improving Megaproject Economics Through the Use of Early Production

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 177729, “Improving Megaproject Economics Through the Use of Early Production,” by James A. Volker and Adam J. Bond, Zakum Development Company, prepared for the 2015 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 9–12 November. The paper has not been peer reviewed. A key aspect of the project discussed in this paper is the use of minimal initial-production facilities to achieve significant early production from each of four preconstructed artificial islands. The initial-production facilities leverage the use of spare processing capacity on existing adjacent satellite platforms to allow for production from each of the islands during the 4-year period between completion of the first wells and completion and startup of the permanent production facilities. Introduction The project is approximately 80 km offshore in the Persian Gulf and consists of four artificial islands. The objective of the initial production phase is to provide early and sustained production from wells drilled on the islands as soon as they are available, thereby achieving advanced revenue generation and improved project economics while the permanent production facilities are under construction. Initial startup was achieved from the first island in November 2014, followed by initial startup of the second island in April 2015. This is the first phase of the plan to increase production from the field by approximately 40%. The project is segmented into an initial- production phase and permanent production buildup phases. The initial-production phase will continue until completion of the first permanent production buildup phase in 2018. The project achieved startup of initial production within 4 years of conceptual design in 2010 and a minimum of 4 years before completion of the permanent production facilities, thereby achieving the goal of capturing the benefits of the initial-production strategy. Benefits and Challenges The initial production strategy evolved and was optimized from conceptual design through front-end engineering and detailed design, resulting in the fit-for-purpose initial-production facilities for the first three islands. Given the short operating duration of the initial-production facilities, cost efficiency was the key driver in decision making. To ensure implementation of only the most cost-effective fit-for- purpose facilities, the early operating experience from the first island was used to simplify further the design of the initial-production facilities on the fourth island.

Stage-specific effects of Notch activation during skeletal myogenesis.

Skeletal myogenesis involves sequential activation, proliferation, self-renewal/differentiation and fusion of myogenic stem cells (satellite cells). Notch signaling is known to be essential for the maintenance of satellite cells, but its function in late-stage myogenesis, i.e. post-differentiation myocytes and post-fusion myotubes, is unknown. Using stage-specific Cre alleles, we uncovered distinct roles of Notch1 in mononucleated myocytes and multinucleated myotubes. Specifically, constitutive Notch1 activation dedifferentiates myocytes into Pax7 quiescent satellite cells, leading to severe defects in muscle growth and regeneration, and postnatal lethality. By contrast, myotube-specific Notch1 activation improves the regeneration and exercise performance of aged and dystrophic muscles. Mechanistically, Notch1 activation in myotubes upregulates the expression of Notch ligands, which modulate Notch signaling in the adjacent satellite cells to enhance their regenerative capacity. These results highlight context-dependent effects of Notch activation during myogenesis, and demonstrate that Notch1 activity improves myotube's function as a stem cell niche.

Sensitivity of satellite interference to locations of small-aperture terminals

Interference to adjacent satellites depends on the specific location of the interfering satellite terminal, and this is an important issue in the case of vehicle-mounted Earth stations (VMES), which use small-aperture antennas. Anticipating large-scale deployments of VMES, regulatory and standards agencies are currently establishing regulations and requirements for VMES. A conventional Earth terminal is required to operate at a fixed location, which could be a very small area around a specific point. Because VMES are mobile, current location-specific regulatory requirements applicable to stationary satellite terminals are not appropriate for VMES. Before establishing suitable location-specific regulations and requirements on VMES, it is necessary to investigate the sensitivity of the interference to the locations of the VMES. In this paper, we provide a detailed investigation of the effects of the locations of the VMES on adjacent satellite interference.

Oxaliplatin enhances gap junction-mediated coupling in cell cultures of mouse trigeminal ganglia

Communications between satellite glial cells and neighboring neurons within sensory ganglia may contribute to neuropathic and inflammatory pain. To elucidate the role of satellite glial cells in chemotherapy-induced pain, we examined the effects of oxaliplatin on the gap junction-mediated coupling between these cells. We also examined whether the gap junction blocker, carbenoxolone, can reverse the coupling.Primary cultures of mice trigeminal ganglia, 24–48h after cell isolation, were used. Satellite glial cells were injected with Lucifer yellow in the presence or absence of oxaliplatin (60μM). In addition, the effect of carbenoxolone (100μM) on coupling, and the expression of connexin 43 proteins were evaluated.Dye coupling between adjacent satellite glial cells was significantly increased (2.3-fold, P<0.05) following a 2h incubation with oxaliplatin. Adding carbenoxolone to the oxaliplatin-treated cultures reversed oxaliplatin-evoked coupling to baseline (P<0.05). Immunostaining showed no difference between expression of connexin 43 in control and oxaliplatin-treated cultures.Our findings indicated that oxaliplatin-increased gap junction-mediated coupling between satellite glial cells in primary cultures of mouse trigeminal ganglia, and carbenoxolone reversed this effect. Hence, it is proposed that increased gap junction-mediated coupling was seen between satellite glial cells in TG. This observation together with our previous data obtained from a behavioral study suggests that this phenomenon might contribute to chemotherapy-induced nociception following oxaliplatin treatment.

Statistical Characterization of Adjacent Satellite Interference for Earth Stations on Mobile Platforms Operating at Ku and Ka Bands

This letter analytically derives the statistical distribution of the carrier-to-noise-plus-interference ratio (CNIR) due to adjacent satellite interference for Earth stations on mobile platforms operating in Ku and Ka frequency bands. At these bands, the adjacent satellite interference problem, which is especially pronounced for mobile terminals, is further aggravated by propagation effects, predominantly rain attenuation. The statistical characterization of the resulting CNIR is of paramount importance in the design of new broadband systems based on digital video broadcasting via satellite 2 extension (DVB-S2x). The statistical derivations are validated by using a CNIR time-series synthesizer developed based on the theory of stochastic differential equations.

The Research about Interference Location Based on Different Times of TDOA with Two Satellites

In this paper, we propose an interference location method based on different times of TDOA (the time difference of arrival) which only used two satellites (the main satellite and its adjacent satellite). Firstly, the model of interference location is built based on two different TDOA data and one spheroid model of earth. Subsequently, a series of practical data of communication satellites are calculated with this model and the trust-region method, aiming to test the validity of the proposed model. Furthermore, comparing with some other methods, such as some researchers based on TDOA and FDOA (the frequency difference of arrival) or TDOA method using three satellites, the result of our method is much more accurate (the interference could be located to 20 km successfully) and more available. Numerical simulations are made to verify the capability and validity of the proposed method.

위성통신 시스템에서 이동형 위성단말을 위한 개루프 전력제어 알고리즘

ABSTRACT In this paper, we propose an open loop power control algorithm to control transmission power of the On-The-Move(OTM) Satcom terminal in GEO satellite communication environment. The proposed algorithm identifies the current channel state restricted by an obstacle or an antenna depointing loss based on the received beacon signal strength. On the basis of the determined signal attenuation causes, the OTM Satcom terminal turns off the RF output when an antenna tracking is failed. If the OTM Satcom terminal experiences a channel blockage by an obstacle, the terminal spreads the transmit data to increase data reception probability. To evaluate the performance of the proposed algorithm, we compare an adjacent satellite interference level and an outage probability. The results show the performance of the proposed algorithm is better than that of the conventional algorithm. 키워드 : 위성통신, 이동형 위성단말, 전력제어, 위성통신채널, 대역확산 Key word : Satellite communications, OTM terminal, Power control, Satellite communication channel, Spread spectrumJournal of the Korea Institute of Information andCommunication Engineering

Interference Studies Between Adjacent Satellite Communications Systems operating Above 10 GHz and Using Power Control as Fade Mitigation Technique

Interference problems are arising from the spectral coexistence between satellite communication networks that operate at frequencies above 10 GHz and particularly when they employ power control as fade mitigation technique. This situation is aggravated due to tropospheric propagation phenomena. In this frequency range, rain attenuation is considered to be the dominant tropospheric fading mechanism. The conditional acceptable intersystem interference probability of the Carrier-to-Interference Ratio of a satellite terminal interfered by an adjacent satellite network is defined as a figure of merit and analytically calculated taking into account a physical-mathematical model for the rainfall medium. The correlated propagation fading phenomena over multiple slant paths are accurately incorporated. The proposed model is flexible and can be applied on a global scale since it incorporates the local climatic conditions concerning the point rainfall rate and the spatial rainfall inhomogeneity. Useful numerical results of the proposed model are obtained and the impact of various crucial operational and geometrical parameters of satellite networks' coexistence is examined. The numerical results have been also verified through simulations using a multi-dimensional rain attenuation synthesizer. Finally, simple and easy-calculated formulas for the satellite communication designers for back of the envelope computations are given.

Belief propagation-based joint iterative algorithm for detection and decoding in asynchronous CDMA satellite systems

As the geostationary orbit (GEO) is congested in the commercial Ku band, the adjacent satellites will receive the interference from small aperture terminals which have a wide field of view. To reduce the interference toward the adjacent satellites, code division multiple access (CDMA) with spread spectrum needs to be adopted in the satellite communications on-the-move system. However, the mutual interference between CDMA users leads to the performance loss, which is not acceptable for the power-sensitive small aperture terminals, and the computation complexity is still an intractable problem when the conventional iterative minimum mean square error (MMSE) scheme is employed to suppress the multiple access interference (MAI) in satellite systems especially that is coded by low-density parity-check (LDPC) code. Moreover, the long transmission delays of different users caused by the long transmission distance require the robustness of the interference suppression for the asynchronous case. In this paper, a joint chip-level algorithm for CDMA multiuser detection and LDPC decoding with a new and simple iterative structure based on belief propagation (BP) for satellite systems is developed, which integrates the iterations of multiuser detection and the iterations of LDPC decoding with factor graphs. Through analysis and simulations, it is verified that the proposed algorithm is robust to the asynchronous CDMA satellite system, and with the similar iterative complexity, the performance of the proposed algorithm outperforms that of the conventional iterative MMSE scheme in the asynchronous CDMA satellite system.

Four-wave mixing and generation of short pulses in multimode class B laser amplifiers

The linear and nonlinear amplification features of an optical signal by a multimode class B laser have been discussed. The four-wave mixing process between the cavity central mode and the amplified input signal produces a sequence of satellite lines. It is demonstrated that short pulses can be formed by phase beating the satellite lines. In the linear regime, the laser amplifier acts like a three-mode free-running laser where the oscillations of two right and left adjacent modes are substituted by those of the amplified input signal and its image satellite line. In the nonlinear regime, two more symmetrical adjacent satellite lines are first added to the cavity electric field components and then the frequency of the cavity central mode is shifted towards the image satellite lines. At the same time, the number of central-mode photons is gradually decreased by raising the input signal strength. The central-mode photons are ultimately reduced to zero, where an injection-locking phenomenon takes place. Finally, we derive a heuristic conservation relation between the input energies to the laser by sum of the pumping and injected signals, and those distributed between the signal and image satellite lines and spontaneous emission radiation.