• Korea journal of population studies
• /
• v.8 no.2
• /
• pp.79-92
• /
• 1985

Fertility has been declined since 1966 (see Table 1). This fertility reduction was duely caused by age at first marriage, induced abortion and contraceptive practice which has been largely increased in recent years. Although tbe proximate determinant such as induced abortion, age at marriage and breastfeeding can and do have an effect on fertility, the principal cause of the reduction in fertility in Korea during the fertility transition can be supported by correlation between level of fertility and contraceptive prevalence (See Fig. 4). Taking a regression equation between fertility (TER. Y) and prevalence level (X), the total fertility rate in 1984 was estimated as 1.9 and 2.1 based on lenear and expotential function shown as follow; $Y_1$=5.709-0.0549 X and $Y_2$_______80________ 1+e2.433+0.017X ($R^2$=O. 93) ($R^2$=0. 96) Where $Y_1$ and $Y_2$ denote total fertility rates obtained through two equations respectivelly. The peak of contraceptive prevalence was assumdd as 80 percent which is almost upper limit in human society. On the other hand, an observed value of 1984 fertility level obtained from five month period shows 2.1 which is coincident with logistic fitting after the adjustment of response error assumed around 10 to 20 percent, At any rate, fertility of Korean women will have been reached replacement level (2.1) by 1985.Thus policy for family planning program must be reviewed toward the direction of integrated approach particularly with MCH program inasmuch as fertility in Korea has already shown population replacement level that require more good quality of service in family planning and their There must be an advanced level of fertility in Korea because wide use of contraception and induced life abortion and age at marriage will effect modern fertility which shows up and down trend between 2.1 and 1.5 in general.

• Journal of the Korean School Mathematics Society
• /
• v.4 no.2
• /
• pp.135-142
• /
• 2001

The selected questions for this study was their conversation in problem solving way of working together. To achieve its purpose researcher I chose more detail questions for this study as follows. $\circled1$ What is the difference of strategy according to its level \ulcorner $\circled2$ What is the mathematical ability difference in problem solving process concerning its level \ulcorner This is the result of the study $\circled1$ Difference in the strategy of each class of students. High class-high class students found rules with trial and error strategy, simplified them and restated them in uncertain framed problems, and write a formula with recalling their theorem and definition and solved them. High class-middle class students' knowledge and understanding of the problem, yet middle class students tended to rely on high class students' problem solving ability, using trial and error strategy. However, middle class-middle class students had difficulties in finding rules to solve the problem and relied upon guessing the answers through illogical way instead of using the strategy of writing a formula. $\circled2$ Mathematical ability difference in problem solving process of each class. There was not much difference between high class-high class and high class-middle class, but with middle class-middle class was very distinctive. High class-high class students were quick in understanding and they chose the right strategy to solve the problem High class-middle class students tried to solve the problem based upon the high class students' ideas and were better than middle class-middle class students in calculating ability to solve the problem. High class-high class students took the process of resection to make the answer, but high class-middle class students relied on high class students' guessing to reconsider other ways of problem-solving. Middle class-middle class students made variables, without knowing how to use them, and solved the problem illogically. Also the accuracy was relatively low and they had difficulties in understanding the definition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.29 no.6
• /
• pp.449-456
• /
• 2018

Herein, several multibeam forming methods that can be applied to microwave wireless power transmission are presented. Because the conventional multibeam forming methods do not consider an active element pattern(AEP), an intended beam shape will contain a steering angle error when applied to an actual system. To solve this problem, a method of considering the average of the AEP and a method of considering all the AEPs by the modified Fourier series method have been proposed. We confirmed that the proposed method reduces the error with the intended beam shape in the multibeam formation. In addition, for the side lobe level(SLL) and null control, a method of multibeam forming by applying the superposition principle to the Dolph-Tschebyscheff method is proposed. We also confirmed that SLL control can be simultaneously achieved with the multibeam formation.

• The Transactions of the Korea Information Processing Society
• /
• v.3 no.4
• /
• pp.938-946
• /
• 1996

Hierarchical subband codec has been widely promoted in the field of data compression/decompression because of their simplicity and modular nature. Over the past years, the study has received great attention to the perfect reconstruction (PR)system which perfectly recovers the original input signal at the reconstructed output. However, in the actual subband codec system, the signals that passed through the analysis filter bank are quantized before transmission to the receiver side and reconstructed by the synthesis filter bank. Thus the PR system is impossible and the quantization effects must be carefully considered in the system design such that the system recovers the reconstructed output as possible to the the original input signal with minimum quantization error.In this paper, we propose an optimum hierarchical subband codec structure in the presence of quantizer. The optimality criteria of the code is given to the deign of the hierarchical analysis/synthesis subband filter bank and the quantizer that minimize then output mean square error due to the quantizer in the codec. Specific opti-mum design esamples are shown with level-1, level-2 hierarchical structure. The optimal designs are verified by computer simulation.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.1
• /
• pp.106-113
• /
• 2008

The starter motor noise is usually well identified by the customers since it is operated while the engine is quiet, and leaves distinct impressions of the vehicle. In this study the design of experiments(DOE) was applied to the identification of the noise sources of direct drive starter motor since this process usually requires lengthy analysis and elaborate experiments. In the first stage of the test, five controllable factors(alignment and dynamic unbalance of armature, tightening torques of T/bolt and center bracket bolt, and alignment of the center bracket-yoke-rear bracket), excluding static unbalance, are sorted out of all possible factors. Test results showed that the dynamic unbalance and misalignment of armature are the major factors. However, the error level of the first test was relatively high, indicating that there might be some missing major factors. In the second stage test the results showed that both static and dynamic unbalances are the dominant factors contributing to more than 80% of the overall noise, while the misalignment contributes around 12%. Error of the second test was about 4% that could be considered satisfactory. The noise level of the optimal product was predicted to be reduced by 19dBA, and verification test showed the average noise reduction of 16.8dBA with the standard deviation of 3.2dBA, and proved the usefulness of the whole DOE process.

• The Journal of the Korea Contents Association
• /
• v.9 no.8
• /
• pp.9-17
• /
• 2009

License plate recognition is an active research area. but few comparative studies on license plate binarization have been conducted. Many related researchers have experienced similar trial and error for finding an effective binarization method. To reduce this trial and error, this study implemented some binarization methods and quantitatively compared the performance of the methods. The performance evaluation consists of a low level measure and a high level measure, so it can evaluate not only the quality of binarized image itself but also the usefulness of the result. The performance evaluation was separately performed with three groups of images so as to understand the properties of the binarization methods. Experimental results show that the quality of binarization is more dependent on the evenness of illumination than the intensity of illumination. The Otsu's method has acquired the most effective performance in the group of even illumination images and the Niblack's method with parameter correction has shown the best quality in the group of uneven illumination images.

• The Korean Nurse
• /
• v.37 no.4
• /
• pp.85-95
• /
• 1998

Because cancer is not curable, patients who suffer from the cancer disease may have physical, psychological and spiritual problems for the rest of their lives. Especially, when cancer patients do not have the meaning in their lives, they will experience spiritual distress seriously. This study was conducted to provide a basis for nursing intervention strategies to minimize the cancer patients' spiritual distress and understand the relationship between the meaning of life and the spiritual distress in cancer patients. The samples were composed of 62 cancer patients who were inpatients or outpatients of three university hospital and one general hospital in Seoul. Data collection was carried out from January 10,1998 to May 30, 1998. Data were analyzed using a SAS program for descriptive statistic, Pearson correlation, t-test, ANOVA, LSD test and linear regression. The results were as follows; 1. The scores on the meaning of life scale ranged from 20 to 140 with a mean of 94. 16(Standard error: 2.79). 2. The scores on the spiritual distress scale ranged from 13 to 91 with a mean of 62. 29(Standard error: 1.38). 3. There were significant correlations between the meaning of life and the spiritual distress(r=.53. p=.00). 4. The linear regression analysis showed that the meaning of life explained 29% of the spiritual distress. 5. In the degree of the meaning of life and the spiritual distress according to the general characteristics, the level of the meaning of life in cancer patients were different by age(F=3. 42, p=.03), marriage status(F=6.06, p=.00), religion(F=4.21, p=.01), thought about treatment of cancer(F=3.76, p=.04). And the level of the spiritual distress in cancer patients were different by religion(F=7.56, p=.00). In conclusion, the meaning of life was identified as important variable that was contributed to reduce the spiritual distress in cancer patients.

• The Korean Journal of Applied Statistics
• /
• v.31 no.2
• /
• pp.303-313
• /
• 2018

This study considers time series models to forecast drug expenditures in national health insurance. We adopt autoregressive error model (ARE) and transfer function model (TFM) with segmented level and trends (before and after 2012) in order to reflect drug price reduction in 2012. The ARE has only a segmented deterministic term to increase the forecasting performance, while the TFM explains a causality mechanism of drug expenditure with closely related exogenous variables. The mechanism is developed by cross-correlations of drug expenditures and exogenous variables. In both models, the level change appears significant and the number of drug users and ratio of elderly patients variables are significant in the TFM. The ARE tends to produce relatively low forecasts that have been influenced by a drug price reduction; however, the TFM does relatively high forecasts that have appropriately reflected the effects of exogenous variables. The ARIMA model without the exogenous variables produce the highest forecasts.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.5
• /
• pp.80-86
• /
• 2010

The conventional bus system architecture consists of masters, slaves, arbiter, decoder and so on in shared bus. As several masters can't use a bus concurrently, arbiter plays an role in arbitrating the bus. The efficiency of bus usage can be determined by the selection of arbitration method. Fixed Priority, Round-Robin, TDMA and Lottery arbitration policies are studied in the conventional arbitration method where the bus priority is primarily considered. In this paper, we propose the arbitration method that calculates the bus utilization of each master. Furthermore, we verify the performance compared with the other arbitration methods through TLM(Transaction Level Model). From the results of performance verification, the arbitration methods of Fixed Priority and Round-Robin can not set the bus utilization and those of TDMA and Lottery happen the error of 50% and 70% respectively compared with bus utilization set by user in more than 100,000 cycles. On the other hand, the bandwidth-award bus arbitration method remains the error of less than 1% since approximately 1000 cycles, compared with bus utilization set by user.

• Geotechnical Engineering
• /
• v.12 no.5
• /
• pp.63-78
• /
• 1996

Various type of in-situ and laboratary tests were performed in order to evaluate the stiffness of sedimentary soft rock. In triaxial compression tests of sedimentary soft rocks, axial strains from the axial displacement of the loading piston or specimen cap conventionally were considerably larger than those measured. tocally on the lateral surfaces of specimen, due to the bedding errors at the top and bottom ends of a specimen. A local deformation transducer was used to measure axial strains free from the bedding error ranging from 0.001% to about 1%. In ultra-sonic wave tests, the elastic modulus of unconfined spec imens was smaller than that of confined specimens, due probably to microfracks. Young's modulus Ed from ultra-sonic wave tests and those at small local strains from triaxial tests were similar, both of which agreed very well with Young's modulus Er from field shear wave velocities. Young'a modulus from the field behaviour was virtually similar to that obtained by reducing Er based on the strain level-dependency of stiffness evaluated by the triaxial tests.