An Analysis of Mutual Interference in Radar Systems Using Dual-Band (Ka / X) Antennas

An analysis of mutual interfering sources on RF systems using dual-band (Ka / X) radar is presented. The purpose of this paper is to improve operational performance of the system from the point of view of EMC design. The experimental dual-band antenna system have decreased the disturbing effects of most mutual interfering sources.

Errors Analysis in Chinese Students＇ Compositions

This paper analyzes the errors in Chinese college students＇ compositions. The study finds that among the three types of errors： interference errors, intralingual errors and developmental errors, developmental errors are the most important errors in the Chinese college students＇ writing. The results will help Chinese EFL teachers （especially college teachers） and students better judge the errors in the English writings of the Chinese students. It will also help the students avoid different kinds of errors in English writing.

Interference of the Cloud to Capacitance Proximity Fuze

Based on the study of the characteristics of the cloud, firstly the interference mechanism of the capacitance proximity fuze passing through the cloud has been studied. Analysis shows that the medium property of the cloud only, has little effect on the capacitance proximity fuze. Secondly, the adherence interference of the cloud to capacitance proximity fuze has been studied for the first time in this paper. Then finite element analysis (FEA) method has been used to simulate the adherence interference of the cloud. Simulation result shows that the cloud adherence effect interferes the output of the capacitance fuze greatly. At last, experiments have been made for the study of the cloud interference.

Lexical Mismatching in Chinese Students＇ EFL Writing

This paper attempts at an in-depth exploration of lexical mismatching, a pattern of vocabulary errors. In this paper, errors per se were collected from 107 writing samples of Chinese college students, and then investigated from a variety of linguistic perspectives. Traditional theoretical approaches, i.e. CA and EA, are incorporated in the source analysis for a more comprehensive interpretation. Hopefully, the findings of the study will shed lights on lexical instruction and acquisition in the field of SLA.

Co-Frequency Interference Analysis Between Ultra-Large-Scale NGSO Constellations and GSO Systems

The rejuvenation of non-geostationary orbit(NGSO)satellite communication holds the promise of seamless and ubiquitous broadband access from the space.However,the NGSO constellations must share the scarce radio spectrum resources with geostationary orbit(GSO)satellite systems,which results in dynamically changing and unevenly distributed interference to GSO systems.In this context,the ultra-large-scale NGSO constellation incurs a more complicated interference environment with GSO systems,which raises urgent demands on inter-system interference evaluation.In this case,we investigate the inter-system downlink interference from a NGSO satellite mega-constellation to a GSO earth station.Specifically,we consider the scenario where the NGSO and GSO earth stations are co-located,and apply a novel visibility analysis method in the interference modeling to reduce computation redundancy.The interference evaluation is then performed through comprehensive simulations,in which the Starlink constellation with more than 4000 satellites is examined for the first time.The simulation results demonstrate various states of interference on the GSO earth station at different deployment locations.It reveals that the number of visible satellites could influence the angle between the main lobe directions of NGSO satellites and the GSO earth station antenna,which further affects the interference level.

Novel scheme for interference avoidance in cognitive radio based cellular networks

The cognitive radio （CR） technology is believed to improve the spectrum efficiency. However, the interference problem has become a critical issue due to the coexistence of primary systems and CR systems. In this paper, the interferences in CR based cellular networks are discussed. Interference scenarios are analyzed, considering different interference sources. Meanwhile, an improved model named ＇Cognitive Interference Ring＇ is introduced to describe the interference range of each secondary user （SU）. Depending on the above analysis, graph coloring based dynamic power allocation （GCDPA） scheme is proposed for interference avoidance. Simulation results demonstrate that in CR based cellular networks, the interferences to primary users （PUs） can be effectively mitigated with the proposed GCDPA scheme, and the system throughput and power efficiency are both improved.