• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.63-66
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• 2015

As smart-phones become popular, mobile data traffic has been dramatically increasing and intensive researches on the next-generation mobile communication network is in progress to meet the increasing demand for mobile data traffic. In particular, heterogeneous network (HetNet) is attracting much interest because it can significantly enhance the network capacity by increasing the spatial resue with macro and small cells. In the HetNet, we have several problems such as load imbalance and interference because of the difference in transmit power between macro and small cells and cell range expansion (CRE) can mitigate the problems. In this paper, we propose a new cell selection scheme with adaptive cell range expansion bias (CREB) for ultra dense HetNet and we analyze the performance of the proposed scheme in terms of average cell transmission rate through system-level simulations and compare it with those of other schemes.

• Health Policy and Management
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• v.24 no.1
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• pp.47-55
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• 2014

Background: Korea is considered to have an integrative health system where both western medicine and Korean (traditional) medicine are officially recognized and provided. Although Korean medicine has been covered by National Health Insurance over 20 years, equity in the utilization of Korean medical care has rarely been examined. Methods: We examined medical care utilization and expenditure of outpatient Korean medicine using panel fixed effects model to remove selection bias. Then we compared it with pooled ordinary least square (OLS) model. This study used Korea Health Panel data, which provides accurate information on out-of-pocket health care payment, including non-covered medical services. Results: Principal findings indicate that the frequency of the utilization of Korean medicine is related with unobservable individual choices different from western medicine, so the panel fixed effect model is appropriate. But pooled OLS model is better fitted for the expenditure of Korean medicine, after controlling for western medical care expenditure. After adjusting for the selection bias, socioeconomic status (income, education) was significantly associated with the expenditure of Korean medicine, but not with the frequency of the utilization of Korean medicine. Conclusion: This study shows that expenditure of Korean medicine utilization is inequitable across socioeconomic groups, which implies that health insurance coverage of Korean medicine is not sufficient.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2311-2317
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• 2011

In this paper, we study the temperature change of a ${\mu}$-bolometer focal plane array with a capacitive transimpedance amplifier bias cancellation circuit. Thermal analysis is essential to understand the performance of a ${\mu}$-bolometer focal plane array, and to improve the temperature stability of a focal plane array characteristics. In this study, the thermal analyses of a ${\mu}$-bolometer and its two reference detectors are carried out as a function of time. The analyses are done with the $30{\mu}m$ pitch $320{\times}240$ focal plane array operating of 60 Hz frame rate and having a columnwise readout. From the results, the temperature increase of a ${\mu}$-bolometer in FPA by an incident IR is estimated as $0.689^{\circ}C$, while the temperature increase by a pulsed bias as $7.1^{\circ}C$, which is about 10 times larger than by IR. The temperature increase of a reference detector by a train of bias pulses may be increased much higher than that of an active ${\mu}$-bolometer. The suppression of temperature increase in a reference bolometer can be done by increasing the thermal conductivity of the reference bolometer, in which the selection of thermal conductivity also determines the range of CTIA output voltage.

• Journal of Haehwa Medicine
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• v.24 no.1
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• pp.15-24
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• 2015

Objectives : This study was carried out to assess the risk of bias of clinical trials on acne treatment with herbal medicine that have been published in Korea. Methods : 7 electronic databases in Korea were searched for clinical trials on acne treatment. Two independent reviewers selected clinical trials on herbal medicine treatment for acne. Selected studies are categorized according to DAMI(Study Design Algorithm for Medical literature of Intervention). RCTs are assessed according to Cochrane RoB(Risk of Bias), non-randomized studies(Before-after studies) are assessed according to RoBANS(Risk of Bias Assessment tool for Non-randomized Study). Results : After selection process, 25 articles are left. Among 25 articles, 3 RCTs and 4 before-after studies are finally included. In RCTs, the proportion of 'unclear' is high in criteria of 'random sequence generation', 'allocation concealment', and 'blinding'. In before-after studies, 'high' is high in criteria of 'blinding for outcome assessment' and 'incomplete outcome data'. Conclusions : Considering the above results of the assessment, it is necessary to conduct more well designed clinical trials on acne treatment with herbal medicine.

• Asia pacific journal of information systems
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• v.3 no.2
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• pp.55-73
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• 1993

The importance of IS project selection process has been recognized by many IS researchers as well as IS practitioners. The ideal selection process should provide an organization with best IS project from many competing proposals. However, researchers have found that some organizational biases exist in making the selection decisions. This means different selection mechanisms favor projects with different characteristics. The purpose of this study is to reexamine previous findings to determine if the biases still exist in rapidly changing IS environment. An exploratory case study was conducted to gain deeper understanding of the actual IS project selection process. Then scenario approach was used for the empirical study. Some conflicting findings from the previous studies are discussed.

• PNF and Movement
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• v.20 no.2
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• pp.147-156
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• 2022

Objective: Electrical stimulation is an assistive technology used to aid the recovery of upper limb use after stroke. The purpose of this systematic review was to determine the effects of electrical stimulation on upper extremity function in individuals with hemiparetic stroke and to develop an evidence base that supports the use of electrical stimulation for upper limb recovery after stroke. Design: A systematic review based on randomized controlled trials (RCTs). Methods: Studies published before April 20 2021 were collected for this review by searching PubMed, four other databases, and RCTs that reported the effects of electrical stimulation on upper extremity function in individuals with the characteristic stroke type. Information on the following parameters was extracted from each study: surname of first author, published year, country, participants, intervention, intervention's intensity, comparison, outcomes, additional therapy, and summary of results. This review also evaluated the bias within each study, including any selection bias, performance bias, detection bias, attrition bias, and reporting bias. Results: This review included five RCTs, and 208 stroke patients were included in the analysis. Stroke patients who underwent electrical stimulation showed significantly improved grip and pinch strengths, wrist range of motion, and basic daily living compared to those in the control group; however, there was no improvement in upper extremity function. Of the selected papers, 60% showed a "high risk" of performance bias, and 20% showed a "high risk" of detection bias. Conclusions: The results of this systematic review suggest that electrical stimulation provides some benefits to stroke patients, such as improved hand strength and range of motion. However, future studies are needed to provide clinical evidence of the effects of electrical stimulation on upper extremity function in stroke patients.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.161-161
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• 2023

Bias correction of values is a necessary step in downscaling coarse and systematically biased global climate models for use in local climate change impact studies. In addition to univariate bias correction methods, many multivariate methods which correct multiple variables jointly - each with their own mathematical designs - have been developed recently. While some literature have focused on the inter-comparison of these multivariate bias correction methods, none have focused extensively on the effect of diverse configurations (i.e., different combinations of input variables to be corrected) of climate variables, particularly high-dimensional ones, on the ability of the different methods to remove biases in uni- and multivariate statistics. This study evaluates the impact of three configurations (inter-variable, inter-spatial, and full dimensional dependence configurations) on four state-of-the-art multivariate bias correction methods in a national-scale domain over South Korea using a gridded approach. An inter-comparison framework evaluating the performance of the different combinations of configurations and bias correction methods in adjusting various climate variable statistics was created. Precipitation, maximum, and minimum temperatures were corrected across 306 high-resolution (0.2°) grid cells and were evaluated. Results show improvements in most methods in correcting various statistics when implementing high-dimensional configurations. However, some instabilities were observed, likely tied to the mathematical designs of the methods, informing that some multivariate bias correction methods are incompatible with high-dimensional configurations highlighting the potential for further improvements in the field, as well as the importance of proper selection of the correction method specific to the needs of the user.

• Journal of the Korean Home Economics Association
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• v.36 no.11
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• pp.209-218
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• 1998

The purpose of this study was to conduct the review of female labor suply, and thus, to provide useful theoretical and empirical frameworks for future studies related to female labor supply. Based on the theory of the allocation of time, the process of individual labor supply was systematically reviewed. Participation Probit/Logit, Tobit, and Selection B;ias Corrected Regression were considered in estimating the function of female labor supply which modifies the selection bias. Based on the previous empirical results, wage rate, asset income, husband's income, the level of eduction, and child-related variables such as the presence of child and the number of children might be considered for the empirical specification of female labor supply.

• Journal of Labour Economics
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• v.26 no.3
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• pp.149-179
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• 2003

This study is analysing the factors determining individuals' behavior of selecting self-employment not only at the micro-level but also at the macro-level to put a particular emphasis on the financial constraint and unemployment rate representing business cycle. The data used in this study are "Korean Labor and Income Panal Study" of the Korea Labor Institute and "Economically Active Population Survey" of National Statistical Office. The main findings are as follows. First, human capital such as educational attainment and job experience has positive effects on male's selection of self-employment. The effects of job experience, however, changed negative for female's selection of self-employment. Second, real estate is significantly enhancing the selection probabilities of employer selection while the income from financial assets has negative effects. Third, entrepreneurial culture and environment are also raising the self-employment selection probability. Lastly, the regional unemployment rate representing the business cycle has positive effects on the self-employment selection after the financial crisis in 1997 both at the micro and macro level. Moreover, the coefficient of regional unemployment rate has changed positive in the structural model of self-employment selection controlling for selection bias and income opportunities, which means that individual's behavior of self-employment selection is rather complex when accounting for the uncertainties of income opportunities and diverse characteristics of self-employment workforce.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.336-339
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• 2007

A sensor having capability to measure two different kinds of ultrasonic waves selectively is described. Under the same bias field configuration, this magnetostrictive type sensor can selectively measure longitudinal waves and flexural ones. Since the switching operation of mode selection is made only by changing the polarity of the permanent magnets used to configure the bias field, it will be very useful after the permanent magnet are interchanged with electromagnets. In order to find the optimal operating bias field, finite elements analysis is used and the condition for flexural wave measurements to meet is found. The linearity of the sensor is verified by experiments and the requirements for linearity also are proposed.