• Korean Journal of Construction Engineering and Management
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• v.6 no.6 s.28
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• pp.133-141
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• 2005

In the resent years, the importance of VE (value engineering) and LCC (life cycle cost) analysis for apartment building construction projects has been fully recognized. Accordingly theoretical models, guidelines, and supporting software systems were developed for the value engineering and life cycle cost analysis for construction management including large building systems. However, the level of consensus on VE and LCC analysis results is still low due to the lack of reliable data on maintenance. This paper presents time dependent LCC model based value analysis method for rational investment decision making and design alternative selection for construction of apartment building. The proposed method incorporates a time dependent LCC model and a performance evaluation technique by fuzzy logic theory to properly handle the uncertainties associated with statistics data and to analyze the value of alternatives more rationally. The presented time dependent VE and LCC analysis procedure were applied to a real world project, and this case study is discussed in the paper. The model and the procedure presented in this study can greatly contribute to design value engineering alternative selection, the estimation of the life cycle cost, and the allocation of budget for apartment building construction projects.

• Journal of Labour Economics
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• v.30 no.3
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• pp.43-75
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• 2007

This study reviews the trend of job separation rates for three years from 2002 to 2005 and investigates the various elements which influence this trend, especially the role of the labor unions, by using Korean Labor Panel data. In the basic statistics, the job retention rate of union members were higher by an average of 28.3% points compared to non-union members, but in the results of controlling the observed variables of individual influences in changing jobs, it was estimated that unions increase the job retention rate by 11% to 13% points. To investigate the effect of unions on the job stability of workers in detail, the non-linear decomposition method developed by Fairlie (2003) was used in the analysis. In examining the difference of job separation rates between union members and non-union members through observed variables of workers in explainable parts and unexplainable parts by using the non-linear decomposition technique, the contribution of the explainable part was estimated to be 67% to 74% and the unexplainable part accounted for the rest which was 26% to 33%. This suggests that not only does the union contribute to the job stability of its members, but the propensity to change jobs for a worker who is a union member is on average lower than that of a worker who is not a union member or who works at an establishment that does not have a union. The results of the empirical analysis show that the job stability effect of labor unions is limited within the boundary of a maximum 7% to 9% points. The reason for the effect of labor unions on job stability being so low is due to various reasons such as collective bargaining structure by company, intensified business competition after the financial crisis, and labor market segmentation.

• Journal of Korea Port Economic Association
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• v.26 no.1
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• pp.222-233
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• 2010

This paper aims at predicting the BDI from Jan. to Dec. 2010 using such econometric techniues of the univariate time series as stochastic ARIMA-type models and Hodrick-Prescott filtering technique. The multivariate cause-effect econometric model is not employed for not assuring a higher degree of forecasting accuracy than the univariate variable model. Such a cause-effect econometric model also fails in adjusting itself for the post-sample. This article introduces the two ARIMA models and five Intervention-ARIMA models. The monthly data cover the period January 2000 through December 2009. The out-of-sample forecasting performance is compared between the ARIMA-type models and the random walk model. Forecasting performance is measured by three summary statistics: root mean squared error (RMSE), mean absolute error (MAE) and mean error (ME). The RMSE and MAE indicate that the ARIMA-type models outperform the random walk model And the mean errors for all models are small in magnitude relative to the MAE's, indicating that all models don't have a tendency of overpredicting or underpredicting systematically in forecasting. The pessimistic ex-ante forecasts are expected to be 2,820 at the end of 2010 compared with the optimistic forecasts of 4,230.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.220-225
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• 2015

This study was conducted to examine O'leary index, patient hygiene performance (PHP) index, and toothbrushing practice assessment in subjects of college students in 20s who had been randomly selected. The purpose of this study is to examine if it is easy for rolling method which is recommended by many dental professionals in Korea to implement and to effectively remove dental plaque. Also, the correlations between dental plaque index and toothbrushing practice assessment with the course of time was confirmed, after instruction session on toothbrushing was provided. STATA 11.0 (StataCorp) was used for analysis. There was no significant difference on the three ways of O'leary index, PHP index, and toothbrushing practice assessment in using rolling method, bass technique and toothpick method when comparing the average resulting from first to third instruction session on toothbrushing. O'leary index, PHP index, and toothbrushing practice assessment were inspected with Kruskal-Wallis test which is used for non-parametric statistics. They were checked three times: the first, before the toothbrushing instruction was given; the second, two weeks after the toothbrushing session was given; and the third, 4 weeks after the session. The results are as follows: O'leary index stood at the lowest in the first experiment but showed the highest in the second (p=0.0001). PHP index was the highest level in the first trial and decreased in the second time, but increased again in the last examination (p=0.0001). Toothbrushing practice assessment also showed a similar tendency with PHP index (p=0.0001). In conclusion, rolling method is not the best option for everyone, and it is thought that more various toothbrushing ways need to be reviewed and recommended to people. Also, institutional framework is required for the continuous education on toothbrushing to be in place as the effectiveness of the education is decreased with time.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.2
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• pp.33-40
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• 2014

At present, Cadastral map of 2 dimensional is in the stream of changing it to 3 dimensional type supported by GPS and laser techniques. In addition, this steam can be explained at the same time with improvement of equipment of storing much information, support of equipment for imaginative 3D spatial information, and support of equipment of expressing land in 3D Cadastral. This study suggest to apply airborne lidar survey technique on cadastral map to acquire comparably and quickly detailed height of ground. For doing this, this study checked out credibility regarding accuracy of airborne lider survey. After choosing research area, this study has done the airborne lidar survey and acquire the result after surveying Cadastral Comparison Point to check out the accuracy of acquired results. In addition, this study check out the result of Cadastral Comparison Point and airborne lidar survey applied by paired sample t-test based on actual results. The result is that test statistics is 0.322 which is 5 % similar level and null hypothesis cannot be rejected, so this study found out that result of both survey ways are the same. Therefore, the result of airborne lidar survey can be utilized to build up 3D Cadastral information hereafter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.6
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• pp.34-51
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• 2008

Today, the Internet is a part of our life. For that reason, we regard revealing characteristics of Internet traffic as an important research theme. However, Internet traffic cannot be easily manipulated because it usually occupy huge capacity. This problem is a serious obstacle to analyze Internet traffic. Many researchers use various sampling techniques to reduce capacity of Internet traffic. In this paper, we compare several famous sampling techniques, and propose efficient sampling scheme. We chose some sampling techniques such as Systematic Sampling, Simple Random Sampling and Stratified Sampling with some sampling intensities such as 1/10, 1/100 and 1/1000. Our observation focused on Traffic Volume, Entropy Analysis and Packet Size Analysis. Both the simple random sampling and the count-based systematic sampling is proper to general case. On the other hand, time-based systematic sampling exhibits relatively bad results. The stratified sampling on Transport Layer Protocols, e.g.. TCP, UDP and so on, shows superior results. Our analysis results suggest that efficient sampling techniques satisfactorily maintain variation of traffic stream according to time change. The entropy analysis endures various sampling techniques well and fits detecting anomalous traffic. We found that a traffic volume diminishment caused by bottleneck could induce wrong results on the entropy analysis. We discovered that Packet Size Distribution perfectly tolerate any packet sampling techniques and intensities.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.7 no.1
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• pp.109-121
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• 2000

Increasingly nursing science is embracing the concepts and methodology derived from psycho-neuroimmunology. It has been previously shown that stress increases and immune function declines in students undergoing examinations. To date, however, no many studies have been reported on stress levels, immune function and interventions in Korean students undergoing their first clinical nursing rotation. It was proposed that nursing students during their first clinical rotation experience increase in stress because of the novelty of the situation and their lack of clinical knowledge. It was also hypothesized that biofeedback and progressive relaxation, methods of self-regulation of involuntary autonomic nervous system responses, would reduce the stress response. The purpose of this study is to test the effectiveness of progressive muscle laxation using biofeedback The effectiveness of the experimental methods was tested by measuring the degree of symptoms of stress (SOS) and the values of ephinephrine, pulse rate, blood pressure and natural killer cells. The subjects of this study were thirty nursing students divided into two groups: experimental group was progressive muscle relaxation group using biofeedback and control group. This study was conducted for 8 weeks of clinical practice. Biofeedback training was done by software developed by J&J company (1-410 form for progressive muscle training). Progressive muscle relaxation training according to Jacobson's Theory was done by messaged word from biofeedback. The data was analyzed using Chronbach' ${\alpha}$ and t-test of the SPSS program and the significance level of statistics was 5%. The results of the study were : 1) The progressive muscle relaxation training using biofeedback was effective for the reduction of symptoms of stress(t=-4.248, p<.001) under clinical practice stress conditions. 2) The progressive muscle relaxation training using biofeedback was not effective for the values of epinephrine(t=-1.294, p=.206). 3) The progressive muscle relaxation training using biofeedback was effective for the reduction of systolic blood pressure (t=-2.757, p=.01). 4) The progressive muscle relaxation training using biofeedback was effective for the reduction of diastolic blood pressure (p=-2.032, 0=.05). 5) The progressive muscle relaxation training using biofeedback was not effective for the reduction of pulse rate(t=-15, p=.988). 6) The progressive muscle relaxation training using biofeedback was effective for the maintenance of natural killer cells (t=2.381, p=02). The first clinical rotation for student nurses is a stressful experience as seen by the rise in the SOS in the control group. Biofeedback using progressive muscle relaxation were effective in preventing the rise of symptoms of stress and the blood pressure means when comparing the pre to post clinical experience, The mean natural killer cell count was depressed in the control group but not significantly different in the experimental groups, It is proposed here that stress via the hypothalamic - pituitary - adrenal axis suppressed the NK cell count whereas the relaxation methods prevented the rise in stress and the resulting immune depression. We recommend relaxation techniques using biofeedback as a health promotion technique to reduce psychological stress. In summary. the progressive muscle relaxation training using biofeedback was effective for the reduction of symptoms of stress under clinical practice stress conditions.

• Journal of muscle and joint health
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• v.4 no.1
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• pp.48-60
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• 1997

This study was undertaken to identify the musculotendinous problems and contributing factors to those problems In students majoring in musical instruments in Korea. The data were collected from March 2, 1996 to March 31, 1996 from 261 music students in various geographical areas. The data were analyzed for descriptive statistics, t-test, chi-square using SPSS $PC^+$ program. The results of this study were as follows : 1. In a questionnaire survey of 261 music students, one hundred twenty five(47.9%) reported having had various musculotendinous symptoms. Twenty seven students among the those who had previous symptoms(21.9%) reported the present symptoms. 2. The experience rates of musculotendinous problems in keyboard players, string players and woodwind players were 50.3%, 48.2%, 33.3% respectively. 3. Most of the students practiced most intensively during their high school years and the musculotendinous symptoms began at the same period. 4. Pain, tenderness and stiffness were the most common symptoms, while paresthesia and motor dysfunction were rare. This indicates that most players had muscle tendinous overuse, while small number had nerve entrapment and motor dysfunction. 5. In past and present symptoms, string players experienced musculotendinous symptoms mainly in both sides of shoulders, lumbar area, left finger, and left wrist, while keyboard players experienced more symptoms in the right wrist, shoulder, fingers than left side. 6. The major contributing factors to the symptoms were weight of instrument, types of instruments, types of daily activities, duration of practice, and playing technique. 7 The most frequent treatment modalities for the symptoms were acupuncture or moxibustion, other alternative therapy such as heat compress and massage. Through this study it was found that the musculotendinous problems might be increased along with their career, due to lack of knowledge about preventive measures and patterns of health behavior seeking alternative modalities rather than professional consultation. Therefore, preventive measures that focus on playing habits such as duration of practice, frequency of rest and position while playing should be developed and taught to the students, their parents, and music educators. Doctors who are interested in this area should attempt to correct the position and posture while playing of the posture. And measures for reduction of loading of instrument weight should also be developed.

• Journal of the Korean Geographical Society
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• v.52 no.1
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• pp.123-141
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• 2017

This study predicted urban green spaces for 2020 based on two scenarios keeping or freeing the green-belt in the Daegu metropolitan city using a hybrid Cellular Automata(CA)-Markov model and analyzed the spatial dynamics of urban green spaces between 2009 and 2020 using a land cover change detection technique and spatial metrics. Markov chain analysis was employed to derive the transition probability for projecting land cover change into the future for 2020 based on two land cover maps in 1998 and 2009 provided by the Ministry of Environment. Multi-criteria evaluation(MCE) was adopted to develop seven suitability maps which were empirically derived in relation to the six restriction factors underlying the land cover change between the years 1998 and 2009. A hybrid CA-Markov model was then implemented to predict the land cover change over an 11 year period to 2020 based on two scenarios keeping or freeing the green-belt. The projected land cover for 2009 was cross-validated with the actual land cover in 2009 using Kappa statistics. Results show that urban green spaces will be remarkably fragmented in the suburban areas such as Dalseong-gun, Seongseo, Ansim and Chilgok in the year 2020 if the Daegu metropolitan city keeps its urbanization at current pace and in case of keeping the green-belt. In case of freeing the green-belt, urban green spaces will be fragmented on the fringes of the green-belt. It is thus required to monitor urban green spaces systematically considering the spatial change patterns identified by this study for sustainably managing them in the Daegu metropolitan city in the near future.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.1-10
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• 2001

In this paper, a multistage parallel interference canceller (MPIC) and a partial multistage parallel interference canceller (PMPIC) are employed as a technique for improving the performance of the asynchronous DS-CDMA systems. The degree of the effect of the timing errors and phase errors on the interference cancellation capability of two types of cancellers is theoretically analyzed and the computer simulation is performed to confirm the analytical results. From the results, the large performance improvement is obtained by employing MPIC and PMPIC with perfect synchronization over the conventional matched filter, and the performance improvement obtained by MPIC and PMPIC is very close to each other as the number of the stage of MPIC and PMPIC increases. When the timing errors and phase errors are considered (in the case of imperfect synchronization), the performance improvement reduces as the performance degradation at the first stage (no cancellation) has a bad effect on the decision statistics at each stage. However MPIC and PMPIC have the strong interference cancellation capability in spite of imperfect synchronization as the number of the stage increases. An interference canceller, which has the strong interference cancellation capability as well as lower complexity for the implementation, is needed for practical systems with timing errors and phase errors because the perfect synchronization is impossible. Therefore, the excellent tradeoff between complexity and performance offered by PMPIC makes it an attractive approach for practical systems.