• International Journal of Computer Science & Network Security
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• v.24 no.2
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• pp.53-58
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• 2024

This paper presents a novel miniaturized 3-D cubic antenna for use in wireless sensor network (WSN) application. The geometry of this antenna is designed as a cube including a meander dipole antenna. A truly omnidirectional pattern is produced by this antenna in both E-plane and H-plane, which allows for non-intermittent communication that is orientation independent. The operating frequency lies in the ISM band (centered in 2.45 GHz). The dimensions of this ultra-compact cubic antenna are 1.25*1.12*1cm3 which features a length dimension λ/11. The coefficient which presents the overall antenna structure is Ka=0.44. The cubic shape of the antenna is allowing for smart packaging, as sensor equipment may be easily integrated into the cube hallow interior. The major constraint of WSN is the energy consumption. The power consumption of radio communication unit is relatively high. So it is necessary to design an antenna which improves the energy efficiency. The parameters considered in this work are the resonant frequency, return loss, efficiency, bandwidth, radiation pattern, gain and the electromagnetic field of the proposed antenna. The specificity of this geometry is that its size is relatively small with an excellent gain and efficiency compared to previously structures (reported in the literature). All results of the simulations were performed by CST Microwave Studio simulation software and validated with HFSS. We used Advanced Design System (ADS) to validate the equivalent scheme of our conception. Input here the part of summary.

• Progress in Medical Physics
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• v.9 no.3
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• pp.175-184
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• 1998

The dose distribution evaluation program for the stereotactic radiosurgery treatment planning system using a gamma knife has been built in order to work on PC. And this custom-made dose distribution is compared with that of commercial treatment planning program. 201 source position of a radiation unit were determined manually using a gamma knife collimator draft and geometrical coordinates. Dose evaluation algorithm was modified for our purpose from the original KULA, a commercial treatment planning program. With the composed program, dose distribution at the center of a spherical phantom, 80 mm in diameter, was evaluated into axial, coronal and sagittal image per each collimator. Along with this evaluated data, the dose distribution at a arbitrary point of inside the phantom was compared with those from KULA. Radiochromic film was set up at the center of the phantom and was irradiated by gamma knife, for the verification of dose distribution. In result, the deviation of the dose distribution from that of KULA is less than ${\pm}$3%, which is equivalent to ${\pm}$0.3 mm in 50% isodose distribution for all examined coordinates and film verification. The custom-made program, GPl is proven to be a good tool for the stereotactic radiosurgery treatment planning program.

• KDI Journal of Economic Policy
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• v.29 no.3
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• pp.29-73
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• 2007

This paper evaluates the effects of the Basic Subsidy Program provided to families with infants cared for in private day care centers. There has been a discrepancy in the price and quality level between public and private day care centers. Public day care centers which receive government support in their labor costs are able to maintain relatively higher quality at lower price than their private counterparts, while the majority of children are cared for at private day care centers. To reduce the gap of the price and quality of care between public and private day care centers by improving the quality and decreasing the price of private day care centers, the Basic Subsidy Program was introduced in 2006 to the private day care centers. The subsidies mainly aim to improve the quality and the accessibility of child care, and encourage mothers' labor supply. For this purpose, the provision of the Basic Subsidy Program imposed prerequisites to the care providers including minimum wage and four major insurances for teachers, and child-staff ratio. I examine whether the subsidies improve the quality of care, help mothers balancing work and family, and increase satisfaction with child care from mothers' perspective. Since the outcome variables that measure the quality of care are difficult to obtain, I instead use the input variables for quality production. Child-staff ratio, teachers' welfare, and care environment are considered. The relationship between these variables and the introduction of subsidies is examined. The 2004 National Survey of Child Care and Education and the 2004 National Survey of Day Care Centers are used for the base data set. To reflect the outcomes after the Basic Subsidy Program, equivalent data sets for households and care providers are constructed by the KDI Data Analysis Unit. Using these nationally representative data sets, information regarding child care is collected. The findings show that the subsidies contribute to the quality of care improving the input variables of quality production. The welfare of teachers is improved, and the child-staff ratio significantly decreases. As a result, the usage of private day care centers greatly increases even though the price level rarely changes. However, mothers' satisfaction with child care are rarely affected by the subsidies. Although the subsidies with no eligibility criteria enlarge the recipients, the actual effects to increase maternal labor supply or to improve satisfaction is limited. Given this findings, I suggest some modifications of subsidies to raise the effectiveness of the subsidy program.