• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.144-151
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• 2002

Future wireless communication systems are expected to provide a broad range of multimedia services in which the asymmetry of traffic load between uplink and downlink is a significant feature. The rode division multiple access system with tune division duplex mode (CDMA/TDD) is a good solution to cope with the traffic asymmetry problem. However. the TDD system is subject to inter-cell interference compared to frequency division duplex (FDD) system. Since both uplink and downlink share the same frequency in TDD. uplink and downlink may interfere each other especially when neighboring cells require different rates of asymmetry. Thus, time slot allocation for tells is an important issue in TDD. In this paper. we propose a genetic algorithm based time slot allocation scheme which maximizes the residual system capacity. The proposed scheme allows that each cell employ different level of uplink/downlink asymmetry and satisfies the interference requirement.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.6
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• pp.82-87
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• 2009

Recently, a great variety of radio services are provided and interference problem between radio systems is being watched remarkably. Therefore, a study of interference between radio systems is needed. In this paper, compatibility between Ultra Wideband (UWB) and Terestrial Digital Multi-media Broadcasting (T-DMB) is analyzed and then distance between them is computed. UWB systems have a very broad frequency characteristic. A big advantage is to share frequency that is already allocated to other systems. T-DMB is a good point that while L-Band is already used for DAB, T_DMB is free of charge. AT-DMB (Advanced T-DMB) is being standardized recently. The result which is analyzed for the interference effects between UWB and T-DMB Systems is 10 [dB], which is value calculated by C/(N0+I), at 80 [m] and then the value is saturated at 150 [m].

• Journal of Ecology and Environment
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• v.34 no.3
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• pp.259-267
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• 2011

A pollen analytical study of sediment sequences collected from Yongneup moor (sampling point: $38^{\circ}$12'57.4" N, $120^{\circ}$7'30.2" E) was conducted to understand the vegetation history in the mountainous region of the central Korean peninsula. Carbon dating was carried out to measure five successive samples obtained from the bottom at a depth of 180 cm to the surface. The Yongneup moor sediment revealed four main local pollen zones; that is, four past vegetation phases as follows: Local pollen zone I: Quercus-Pinus zone; estimated age, 5,900-4,800 calibrated years (cal) before present (BP); vegetation type, cool-temperate central/montane deciduous broad-leaved forest. Local pollen zone II: Pinus-Abies-Quercus zone; estimated age, 4,800-3,400 cal BP; vegetation type, cool-temperate northern/alti-montane mixed coniferous and deciduous broad-leaved forest. Local pollen zone III: Quercus-Pinus-Abies zone; estimated age, 3,400-400 cal BP; vegetation type: cool-temperate central/montane deciduous broad-leaved forest. Local pollen zone IV: Pinus-Quercus zone; estimated age, 400-present cal BP; vegetation type, cool-temperate central/montane mixed deciduous broad-leaved and coniferous forest. It was confirmed that subalpine coniferous forests had expanded to the mountainous region of the central Korean peninsula during the period from 4,800-3,400 cal BP and thereafter deciduous forests dominated by Q. mongolica were established. Notably, secondary forests dominated by P. densiflora developed in the lower part of the mountainous region of the central Korean peninsula about 400 cal BP due to human interference.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.437-443
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• 2003

A interference of outside electric source and electric fast transient(EFT) are origins of destroy and malfunction in the precise electrical and electronic equipments. It makes a serious obstacle as the form of conducted noise. Therefore, it is strongly needed to protect precision electrical and electronic equipments from the interference and EFT. In this research, a EMC filter composed of feed-through capacitors and ferrite beads of high permeability is designed and it＇s properties are investigated for PDP. The filter produced in this research have wide band frequency characteristics and more than 40 dB reflection loss in the frequence of 10 MHz∼1.5 GHz which satisfy the standard of CISPR Pub. 22 and the level 4 of IEC 61000-4-4.

• Current Photovoltaic Research
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• v.5 no.2
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• pp.55-58
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• 2017

We investigated the influences of dielectric thin film coating on the optical characteristics of c-Si wafers with nanocone (NC) arrays using finite-difference time-domain (FDTD) simulations. Dielectric thin films on high-refractive-index surface can lower optical reflection and reflection dips appear at the wavelengths where destructive interference occurs. The optical reflection of the NC arrays was lower than that of the dielectric-coated planar wafer in broad wavelength range. Remarkable antireflection effects of the NC array could be attributed to beneficial roles of the NCs, including the graded refractive index, multiple reflection, diffraction, and Mie resonance. Dielectric thin films modified the optical reflection spectra of the NC arrays, which could not be explained by the interference alone. The optical properties of the dielectric-coated NC arrays were determined by the inherent optical characteristics of the NC arrays.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.143-148
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• 2013

A novel ultracompact polarization beam-splitter (PBS) combining two plasmonic multimode interference couplers (P-MMICs) and DFB guiding structure is implemented. The $2{\times}1$ and $1{\times}2$ P-MMICs are designed to collect the polarized powers of TE and TM modes reflected by or transmitted through an internal DFB structure. The simulation results show that the designed DFB-assisted PBS is very short (about $75{\mu}m$), and has a low insertion loss, a high extinction ratio, and a broad bandwidth of 20 nm.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.9
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• pp.321-331
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• 2021

This study examines the impact of Information and Communication Technology (ICT) and the role of Malaysian local wisdom called "Ugahari" in managing Work-Life Balance (WLB) during the COVID-19 pandemic in Malaysia. Data was obtained through online and offline surveys which were distributed to the agencies in the public and private sectors spread across Kuala Lumpur, Selangor and Pura Jaya. Overall 466 respondents were found to have given valid and complete responses. This research utilized the Partial Least Squares Structural Equation Modelling. It was found that the use of the ICT during Work from Home (WFH) helped workers to have relatively high flexibility where they could easily expand or contract one domain to meet the demands of another domain. At the same time it also offered high permeability where aspects of one domain entered another domain. This encourages workers to integrate their roles and achieve broad work autonomy. Furthermore, this situation then gives rise to a high level of interference at the boundary between work and family domains. On the other hand Ugahari reduces the level of interference caused by ICT use and encourages workers to compartmentalize their respective roles. Thus, ICT and Ugahari's behavior can play a role and complement each other in the context of realizing worker well-being.

• Korean Journal of Environment and Ecology
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• v.18 no.4
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• pp.369-381
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• 2004

This study was achieved to present the way to restore the Seonheulgot pasture-grassland damaged by landuse and interference for a long time to evergreen broad-leaved forests as the native vegetation structure. As a result of analyzing ecological succession tendency of structure in survey area, we established the optimal restoration model. The total of survey sites were 26, and the classified plant community types were four types by M.I.P of dominant woody species. Finally we classified the four types based on diameter of dominant woody species in canopy layer. The six community types are as follows: Community I was runner-shrub forest, community II was evergreen broad-leaved shrub forest, and community III was evergreen broad-leaved forest of small diameter. Community IV and V were evergreen broad-leaved forest of middle diameter. Community Ⅵ was evergreen broad-leaved forest of large diameter. The number of constituent species was 24 in community I, 28 in community II as the shrub forest, 16 as the evergreen broad-leaved forest of small diameter, 29 in community III, 30 in community IV as the evergreen broad-leaved forest of middle diameter and 27 in community Ⅵ as the evergreen broad-leaved forest of large diameter. The range of Shannon's index of all communitys was from 0.8763 to 1.2630 and the Similarity index between the community composed of middle diameter woody species and large diameter woody species. The ecological succession of community I, II, and III were changed from pasture-grassland to broad-leaved forest and the structure of community IV, V, and Ⅵ was similar to evergreen broad-leaved forest in warm temperate region. We suggest the restoration planting model evergreen broad-leaved forest of in Seonheulgot pasture-grassland, as follows: The target restoration vegetation were Castanopsis cuspidata var. sievoldii community and Queycus glauca community. Castanopsis cuspidata var. sievoldii and Quercus glauca should be dominant woody species in canopy layer, the number of trees was 10 per 100$m^2$, and Castanopsis cuspidata var, sievoldii, Quercus glauca, Camellia japonica, and Eurya japonica should be dominant woody species in the understory layer, the number of trees was 14 per 100$m^2$.

• Journal of electromagnetic engineering and science
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• v.13 no.1
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• pp.34-37
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• 2013

This paper presents a novel ultra-wideband (UWB) antenna that rejects narrow and broad bands and is suitable for wireless communications. The base of the proposed antenna has a circular patch that can cover the UWB frequency range (3.1~10.6 GHz). The interference issues caused by co-existence within the UWB operation frequency are overcome by a design that uses a parallel-coupled asymmetric dual-line with a circular monopole antenna. The proposed antenna showed a stable radiation pattern, realized gain and reflection coefficient lower than -10 dB across the UWB operation bandwidth except for 5.15~5.85 GHz and 7.25~8.4 GHz. The fabrication, simulation, and measurement results obtained for the proposed antenna were in good agreement with the expected values.

• Journal of Magnetics
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• v.5 no.3
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• pp.76-80
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• 2000

Soft x-ray standing waves produced by a multilayer interference substrate add depth-sensitivity to magnetic circular dichroism to resolve changes in Co magnetism across a 10${\AA}$ distance from the Co center to the Co-Pd interface of a Pd/Co/Pd trilayer having in-plane magnetization. Large enhancements of in-plane orbital and spin magnetic moments, as well as the number of d holes, are strongly localized in a thin interface layer. These results provide new insight into the phenomenon of magnetic anisotropy at buried interfaces, and suggest a broad applicability of such standing wave measurements to interface magnetism studies.