• Journal of radiological science and technology
• /
• v.15 no.2
• /
• pp.31-36
• /
• 1992

Grids can improve the diagnostic quality of chest radiography by trapping the greater part of scattered radiation thus providing more detailed. chest radiographic images. It is most effective mathod of reduce the scatter ratio but must increase the expour factor. The benefit of use of grid is improve the contrast and the loss is increase of patient dose. In chest radiography especially hard quality high voltage radiography it will have to be considered to select the optimum grid with view point of benefit and loss. In this experiment, author got some result of characteristics about 4 different grids with film method. 1. There was no difference the scatter ratio in case of no grid and the scatter ratio was about 60%. 2. 16 : 1 grid was excellent of scatter reduction factor in high voltage chest radiography, next was 10 : 1, CROSS, MICRO FINE grid have low scatter reduction rate compare to 16:1, 10:1 grid. 3. The bucky factor of CROSS grid in accordance of kVp was find out the highest in 4 grids, on the contraly 10 : 1 grid was profitable to the exposure does. 4. With careful consideration in the point of scatter reducion rate and bucky factor, author suggest the 10 : 1 linear grid on the use of chest radiography in $80{\sim}120\;kVp$, 16 : 1 grid in $120{\sim}140\;kVp$.

• Korean Journal of Health Education and Promotion
• /
• v.33 no.2
• /
• pp.77-87
• /
• 2016

Objectives: This study was conducted to provide data in order to develop effective family planning programs by analyzing the factors which affect contraceptive use among women in Ethiopia. Methods: The community health survey was conducted on women of childbearing age. The research model was developed based on Andersen's Model. A total of 320 respondents were analyzed through Chi-square analysis, t-tests and logistic regression analysis. Results: Contraceptive prevalence rate was 43.1% and most of them were using modern and short-term methods. Among three factor categories, the need factor(unwanted pregnancy experience) was revealed as the most important factor, following enabling factor which was knowing the FP services in health center. Conclusions: These results lead to several conclusions. First, the results imply that programs should focus on women who are in the over 30yr. as well as the poorer economic group and urban residents. Second, to improve the effectiveness of the program, it is important to help them to be motivated themselves and to promote knowledge on various methods. Third, in terms of service delivery, community health workers are expected to take a crucial role. To improve the availability of services, they should provide practical services as those in health center.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.2
• /
• pp.87-96
• /
• 2004

This paper summarizes the research results of the load management for pole transformers done in 1997-1998 and 2000-2002. The purpose of the research is to enhance the accuracy of peak load estimation in pole transformers. We concentrated our effort on the acquisition of massive actual load data for modifying the load regression coefficients, which related to the peak load estimation of lamp-use customers, and adjusting the demand-factor coefficients, which used for the peak load prediction of motor-use customers. To enhance the load regression equations, the 264 load data acquisition devices are equipped to the sample pole transformers. For the modification of demand factor coefficients, the peak load currents are measured in each customer and pole transformer for 13 KEPCO (Korea Electric Power Corporation) distribution branch offices. Case studies for 50 sample pole transformers show that the proposed coefficients could reduce estimating error of the peak load for pole transformers, compared with the conventional one.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.4 no.2
• /
• pp.83-87
• /
• 2004

Phase noise performance and current consumption of Radio Frequency (RF) Voltage-Controlled Oscillator (VCO) are largely dependent on the Quality (Q) factor of inductor-capacitor (LC) tank. Because the Q-factor of LC tank is determined by on-chip spiral inductor, we designed, analyzed, and modeled on-chip differential inductor to enhance differential Q-factor, reduce current consumption and save silicon area. The simulated inductance is 3.3 nH and Q-factor is 15 at 2 GHz. Self-resonance frequency is as high as 13 GHz. To verify its use to RF applications, we designed 2 GHz differential LC VCO. The measurement result of phase noise is -112 dBc/Hz at an offset frequency of 100 kHz from a 2GHz carrier frequency. Tuning range is about 500 MHz (25%), and current consumption varies from 5mA to 8.4 mA using bias control technique. Implemented in $0.35-{\mu}m$ SiGe BiCMOS technology, the VCO occupies $400\;um{\times}800\;um$ of silicon area.

• Journal of the Korea Society of Computer and Information
• /
• v.21 no.9
• /
• pp.113-119
• /
• 2016

In this paper, a research model is proved empirically which includes factors related on the purchase intention of smart car as high innovative product in advance of commercialization. As one of relating to consumer's expectation benefit factors, individual attribute factor includes product knowledge, individual innovativeness, and sociality. Consumer's expectation benefit factor includes perceived ease-of-use, usefulness, and enjoyment. As of switching cost variables, there are financial, uncertainty, relational and psychological switching costs factors. Analysis were performed using data from the 257 respondents as random sampling among potential consumers. Purchase intention were affected by individual innovativeness mediated by perceived enjoyment, and individual sociality by perceived ease-of-use and enjoyment also. Relational switching costs factor was only a significant control variable between purchase intention with consumer's expectation benefit factor. This result presents some implications for making the new smart car's detail concept and marketing strategy related to targeting the consumer as high innovative product and technology firms including smart car makers.

• Journal of Information Processing Systems
• /
• v.16 no.4
• /
• pp.784-794
• /
• 2020

In order to effectively evaluate the urban water security, the study investigates a novel system to assess factors that impact urban water security and builds an urban water poverty evaluation index system. Based on the contribution rates of Resource, Access, Capacity, Use, and Environment, the study adopts the Water Poverty Index (WPI) model to evaluate the water poverty levels of 14 cities in Gansu during 2011-2018 and uses the least variance method to evaluate water poverty space drive types. The case study results show that the water poverty space drive types of 14 cites fall into four categories. The first category is the dual factor dominant type driven by environment and resources, which includes Lanzhou, Qingyang, Jiuquan, and Jiayuguan. The second category is the three-factor dominant type driven by Access, Use, and Capability, which includes Longnan, Linxia, and Gannan. The third category is the four-factor dominant type driven by Resource, Access, Capability, and Environment, which includes Jinchang, Pingliang, Wuwei, Baiyin, and Zhangye. The fourth category is the five-factor dominant type, which includes Tianshui and Dingxi. The driven types impacting the urban water security factors reflected by the WPI and its model are clear and accurate. The divisions of the urban water security level supply a reliable theoretical and numerical basis for an urban water security early warning mechanism.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.5 no.1
• /
• pp.31-38
• /
• 1980

The purpose of this paper is to exhibit existing replacement models and to develop new replacement models for managing equipments in large organizations, private or public. Some of the models in this paper are well known and in use, and some are not. All these models are classified, depending on main factors which play key roles on the models. One group is the models in which the economic factor plays a key role, and the other is those in which both the economic factor and the effectiveness factor play key roles.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2007.05a
• /
• pp.15-20
• /
• 2007

In this paper we introduce the IP3003 which provides excellent Power Factor and Total Harmonic Distortion to the power system. It is developed by Interpion Semiconductor co. LTD. However, the efficiency of power factor correction system is very difficult to analyze mathematically. In this paper, we use the numerical simulation methods for analyzing PFC systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.89-93
• /
• 2002

In the present paper we suggested a parallel-branch structure of aluminum spiral inductor for the use of RF integrated circuit at 1∼3 GHz. The inductor was implemented on P-type silicon wafer (5∼15 Ω-cm) under the standard CMOS process and it showed a improved quality(Q) factor by more than 10% with no degradation of inductance. The effect of the structure modification on the Q factor and the inductance was scrutinized comparing with those of the conventional spiral inductors.

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1998.08a
• /
• pp.470-474
• /
• 1998

In this paper, to estimate the time-varying parameters of speech signal, we use the robust sequential estimator based on t-distribution and, for time-varying signal, introduce the forgetting factor. By using the RSE based on t-distribution with small degree of freedom, we can alleviate efficiently the effects of outliers to obtain the better performance of parameter estimation. Moreover, by the forgetting factor, the proposed algorithm can estimate the accurate parameters under the rapid variation of speech signal.