• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.11
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• pp.675-681
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• 2014

As the recently soaring wireless traffic, small-cell techniques have been actively studied in order to support such a wireless demand for cellular wireless networks. This paper studies interference mitigation methods for random-access small-cell networks. Although inter-cell interference between small random-access cells is one of the main factors to degrade overall performance, most of the previous works focused on interference mitigation between users in each cell. To address such limitation, dynamic opportunistic interference alignment is proposed exploiting statistical characteristics of random-access. It is demonstrated by simulation that the proposed scheme outperforms the previous approach as the number of cells or the number of users in each cell increases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.621-624
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• 2001

A metal sheath provides a cable with electrostatic screening and a degree of magnetic screening. The presence of a screen on a cable also reduces the induction arising from the high-frequency components of transients caused by power-line switching and also induced transients from lightning strokes; such transient induced voltages are of increasing importance with the increasing use of miniaturized telecommunication equipment with very small thermal capacity. This paper describes electrostatic induction and electromagnetic induction caused by power interference. Also screening factors are proposed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.2
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• pp.56-63
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• 2003

We investigate some implementation factors that affect the performance of multi-rate parallel interference cancellers (PICs) for the international mobile telecommunications-2000 (IMT-2000) 3rd-generation partnership project (3GPP) system. We consider the simple multi-rate PIC [1,2] that can remove effectively multiple access interference (MAI) through block-based detection and sample-based cancellation in asynchronous user environments. The PIC structure has significantly lower complexity as compared with that of the existing scheme, especially as the number of users increases. We analyze the effects of timing error, oversampling rate, unsynchronized users and/or outer-cell interference, and the number of Quantization bits on the PIE performance through extensive computer simulations. The models for such factors and the optimum parameters are drawn. Finally, we evaluate the receiver complexities of the PIC receivers employing using the advanced removal scheme.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.691-693
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• 2015

Radio sources are very weak, as they can travel through large distances. Radio sources also have photons with low energies compared to others electromagnetic waves (EM). Microwave photons have a little more energy than radio waves, infrared photons have still more, then visible, ultraviolet, X-rays, and the most energetic electromagnetic wave is gamma-rays. Radio astronomy studies are restricted due to radio frequency interference (RFI) produced by people. If this disturbance is not minimized, it poses critical problems for astrophysical studies. The purpose of this paper is to profile RFI maps in Peninsular Malaysia with a minimum mapping technique for RFI interference. Decision-making processes using GIS (Geographical Information System) for the selection requires gathering information for a variety of parameters. These factors affecting the selection process are also taken into account. In this study, various factors or parameters are involved, such as the availability of telecommunications transmission (including radio and television), rainfall, water lines and human activity. This mapping step must be followed by RFI site testing in order to identify areas of low RFI. This study will benefit radio astronomy research, especially regarding the RFI profile.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.5
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• pp.72-84
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• 1998

In order ot study the influence of a circular inclusion on a stress field near a crack tip, mutual interference of a slant crack and the circular inclusion is analyzed of a bimaterial inclusion. As the crack emanates at the equivalent slant crack angle the correction factors FⅠ and FⅡ for the inclusion wit small Young's modulus were found to decrease as the inclusion radius increased. The correction factors for inclusion with large Young's modulus increase as the inclusion radius increases at the equivalent radius of the inclusion, the correction factors decrease as the slant crack angle increases for the aspect ratio $\frac{c}{W}$ = 0.1 irrespective of the Young's modulus. For $\frac{c}{W}$ greater than 0.2, they increase as the slant crack angle increases. There is no influence of stress mutual interfce after crack emanates beyond the inclusion radius.

• Asian Oncology Nursing
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• v.12 no.4
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• pp.339-346
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• 2012

Purpose: The purpose of this study was conducted to identify the impact of Symptom Severity and Symptom Interference on Sleep Disturbance among cancer patients. Methods: This study was conducted from October 8th to October 25th, 2012. One hundred eight cancer patients were recruited from S city in Korea. The instruments used in this study were the Symptom Severity, Symptom Interference and the Sleep Disturbance scales for patients with cancer. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficients and multiple regression with the SPSS/WIN 20.0 program. Results: The Sleep Disturbance for cancer patients showed a significant relationship with Symptom Interference and cancer stage. The significant factors influencing Sleep Disturbance were Symptom Severity and Symptom Interference. They explained 40.5% of the variance in stage IV. Conclusion: Patients with cancer experienced Symptom Severity and Symptom Interference which led to a negative effect on Sleep Disturbance. The results suggest that intervention programs to reduce Symptom Severity, Symptom Interference could improve Sleep Disturbance for cancer patients.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9B
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• pp.1608-1615
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• 1999

In this study, we investigate the inter cell interference of LMDS(Local multipoint Distribution Service) system cell in LMDS system design process. There are several interference sources in LMDS system but we consider co-channel adjacent interference, cross-polarization interference, tx/rx interworking interference as three major factors. As the summation of each interference, C/N is keep 19 dB in 2km range but decreased gradually over 2km. Based on theoretical results, we process the experimental test and get results that C/I=20 dB have to be maintained to transmit the data successfully under rain fall attenuation condition. This experiential results are similar to the theoretical analysis results we examined.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.8
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• pp.645-650
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• 2010

The continuous increase demand for electric power leads to the additional construction of transmission facilities, but it is not easy to acquire right-of-way for transmission facilities. Therefor, there is a need for compact tower that can be built on a narrow right-of-way the compact tower with polymer insulation arm is a solution. It can be upgrading conventional 154 kV transmission line voltages to 345 kV levels. However transmission voltage is increasing, environment interference (corona noise, radio interference, etc.) will occur gradually. This environment interference is depending on the electrical clearances of tower and configuration of conductors. Therefore the analysis of the factors of environmental interference is necessary in order to upgrading transmission voltage. This paper presents the design factor of a compact tower to meet the environmental interference standard.

• Wind and Structures
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• v.31 no.5
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• pp.431-443
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• 2020

The modern tall buildings are often constructed as an unconventional plan and as twin buildings. Wind load on the tall building is significantly influenced by the presence of another building in the near vicinity. So, it is imperative to study wind forces on an unconventional plan shaped tall building. Mean wind pressure coefficients of a square and 'H' plan shape tall buildings are investigated using wind tunnel experiments. The experiments were carried out for various wind directions from 00 to 900 at an interval of 300 and various locations of the identical interfering building. The experimental results are presented at the windward face from the viewpoint of effects on cladding design. To quantify the interference effects, interference factors (I.F) are calculated. Mean pressure coefficients of both models are compared for isolated and interference conditions. The results show that pressure reduces with an increase in wind angle till 600 wind direction. The interfering building at full blockage interference condition generates more suction than the other two conditions. The interference factor for both models is less than unity. H-plan building model is subjected to a higher pressure than the square model.

• ETRI Journal
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• v.36 no.4
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• pp.519-527
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• 2014

An integrated multi-beam satellite and multi-cell terrestrial system is an attractive means for highly efficient communication due to the fact that the two components (satellite and terrestrial) make the most of each other's resources. In this paper, a terrestrial component reuses a satellite's resources under the control of the satellite's network management system. This allows the resource allocation for the satellite and terrestrial components to be coordinated to optimize spectral efficiency and increase overall system capacity. In such a system, the satellite resources reused in the terrestrial component may bring about severe interference, which is one of the main factors affecting system capacity. Under this consideration, the objective of this paper is to achieve an optimized resource allocation in both components in such a way as to minimize any resulting inter-component interference. The objective of the proposed scheme is to mitigate this inter-component interference by optimizing the total transmission power - the result of which can lead to an increase in capacity. The simulation results in this paper illustrate that the proposed scheme affords a more energy-efficient system to be implemented, compared to a conventional power management scheme, by allocating the bandwidth uniformly regardless of the amount of interference or traffic demand.