• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.284-284
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• 2011

Ion sensitive field effect transistor (ISFET)는 용액 중의 각종 이온 농도를 측정하는 반도체 이온 센서이다. ISFET는 작은 소자 크기, 견고한 구조, 즉각적인 반응속도, 기존의 CMOS공정과 호환이 가능하다는 장점이 있다. ISFET의 기본 구조는 기존의 metal oxide semiconductor field effect transistor (MOSFET)에서 고안되었으며, ISFET는 기존의 MOSFET의 게이트 전극 부분이 기준전극과 전해질로 대체되어진 구조를 가지고 있다. ISFET소자의 pH 감지 메커니즘은 감지막의 표면에서 pH용액의 수소이온이 막의 표면에 속박되어 표면전위의 변화를 유발하는 것에 기인한다. 그 결과, 수소이온의 농도에 따라 ISFET의 문턱전압의 변화를 일으키게 되고 드레인 전류의 양 또한 달라지게 된다. 한편, ISFET의 좋은 pH감지특성과 높은 출력특성을 얻기 위하여 high-k물질들이 감지막으로써 지속적으로 연구되어져 왔다. 그 중 Al2O3와 HfO2는 높은 유전상수와 좋은 pH 감지능력으로 인하여 많은 연구가 이루어져온 물질이다. 하지만 HfO2는 높은 유전상수를 갖음에도 불구하고 화학용액에 대한 non-ideal 효과에 취약하다는 보고가 있다. 반면에 Al2O3의 유전상수는 HfO2보다 작지만 화학용액으로 인한 손상에 대하여 강한 immunity가 있는 재료이다. 본 연구에서는, 이러한 각각의 high-k 물질들의 단점을 보안하기 위하여 SiO2/HfO2/Al2O3(OHA) 적층막을 이용한 ISFET pH 센서를 제작하였으며 SOI 기판에서 구현되었다. SOI기판에서 OHA 적층막을 이용한 ISFET 제작이 이루어짐에 따라서 소자의 signal to noise 비율을 증대 시킬것으로 기대된다. 실제로 SOI-ISFET와 같이 제작된 SOI-MOSFET는 1.8${\times}$1010의 높은 on/off 전류 비율을을 보였으며 65 mV/dec의 subthreshold swing 값을 갖음으로써, 우수한 전기적 특성을 보이는 ISFET가 제작이 되었음을 확인 하였다. OHA 감지 적층막의 각 층은 양호한 계면상태, 높은 출력특성, 화학용액에 대한non-ideal 효과에 강한 immunity을 위하여 적층되었다. 결론적으로 SOI과 OHA 적층감지막을 이용하여 우수한 pH 감지 특성을 보이는 pH 센서가 제작되었다.

• Journal of Korea Port Economic Association
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• v.31 no.3
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• pp.75-91
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• 2015

This study aims to assess the competitiveness of 30 logistics centers that operate in the hinterland of the North Container Port at Busan New Port. Thirty-two key factors were selected from previous studies to analyze and improve competitiveness and expand business opportunities in the hinterland. Suggestions from logistics experts were also canvassed. These variables were then put through first- and second-factor analysis to verify validity and measure confidence levels; they were later categorized into five factors and 15 sub-factors impacting on competitiveness. The categorized factors were compared using the analytic hierarchy process (AHP) to assess the importance of each factor and sub-factor in the case of logistics centers in the North Container hinterland of Busan New Port. The findings indicate that factors related to the securing of significant amounts of container cargoes were of greater importance. On the other hand, relatively basic factors proved to be less important in improving the competitiveness of the port hinterland.

• Smart Media Journal
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• v.9 no.2
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• pp.86-91
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• 2020

The current trend of the education market is the development of the fourth industrial revolution and the development of ICT, and various technologies are developing into edu-tech technology that is integrated into the education system. In particular, the market for edu-tech systems capable of lifelike immersive learning effects in virtual space is expanding. However, education in Korean medicine is not objective because of the absence of educational simulators and systems to train and evaluate acupuncture. In this paper, we propose an acupuncture controller and a human body model to increase the effectiveness of acupuncture point training as a follow-up study of "Design of Acupuncture Contents and Dummy for Acupuncture Point Training System". Through the proposed acupuncture controller and Dummy, the accuracy of acupuncture points for the acupuncture point data matching and content motion recognition rate is presented. In addition, the results of temperature and humidity and temperature change tests for evaluating the environmental reliability of the controller are presented.

• Korean Journal of Social Welfare
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• v.66 no.1
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• pp.277-306
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• 2014

The purpose of this study was to develop the first social work values scale in Korea. Its development would be expected to increase empirical studies on social work values. Based upon the literature review of social work values, the examination of codes of ethics as well as existing scales, and the comments from professionals in this field, 62 preliminary items were developed. Preliminary items were evaluated with a total of 521 social workers who were working in various fields of social work in Seoul and surrounding areas. A series of exploratory factor analyses were conducted to find out the optimal structure of the scale. After deleting 29 items with low factor loadings or being cross-loaded, the scale is composed of three factors with each factor having 11 items. Confirmatory factor analysis confirmed the factor structure of the scale obtained by exploratory factor analysis. The first factor was named autonomy, the second factor was named equality, and third factor was named paternalistic intervention. Each component of the social work values scale is found to be reliable and valid.

• Journal of Service Research and Studies
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• v.5 no.1
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• pp.1-15
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• 2015

Service has its aim to maximize customer loyalty for companies to improve business productivity by differentiation from the competition. Public transport services using, the needs and demands of consumers also appear very differently than in the past, looking at the service of the company eye-level of the consumer Is increasing more and more. In order to survive in this environment, companies work together to improve the level of service and ensure customer loyalty is essential. In order to improve our service. What's more, it can be said that it is important to actively participate in the work of the internal customer, employee morale boost. In order to improve customer satisfaction has a service-oriented members should respond to customers and make a good company to work also affects the internal staff to verify this service-oriented and affect. In this study, to be urban rail service orientation of the staff working in the field of operational agencies in the future to measure the impact of many companies to promote the GWP proposes to create a good business implications.

• Journal of Digital Convergence
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• v.16 no.10
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• pp.145-153
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• 2018

Recently the Korean society has suffered severe conflicts over the rate of increase in the minimum wage, while academics have failed to provide appropriate standards through reliable research. Recent foreign studies using natural experimentation or meta-regression analysis show that the increase in minimum wage has little effect on employment. Domestic studies are not yet numerous in number, and they present different conclusions on employment effects depending on the data used, sample period, and research model. To properly assess the employment effects of the minimum wage, future studies should minimize measurement errors in minimum wage dataset, and appropriately consider the endogenous change of minimum wage, economic situation and trends of employment changes. It is also necessary to utilize natural experiment methods before and after the increase of the minimum wage.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.43-50
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• 2016

NAND flash based storage devices adopts multi-channel and multi-way architecture to improve performance using parallel operation of multiple NAND devices. However, multiple NAND devices consume higher current and peak power overlap problem influences on the system stability and data reliability. In this paper, current waveform is measured for erase, program and read operations, peak current and model is defined by profiling method, and estimated probability of peak current overlap among NAND devices. Also, system level TLM simulator is developed to analyze peak overlap phenomenon depending on various simulation scenario. In order to remove peak overlapping, token-ring based simple power management method is applied in the simulation experiments. The optimal peak overlap ratio is proposed to minimize performance degradation based on relationship between peak current overlapping and system performance.

• Physical Therapy Korea
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• v.23 no.3
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• pp.40-47
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• 2016

Background: Assessments of Sit-to-Stand (STS) and gait functions are essential procedures in evaluating level of independence for the patients after stroke. In a previous study, we developed the software to analyze center of pressure (COP) in standing position on Wii Balance Board (WBB). Objects: This purpose of this study is to measure test-retest reliability of ground reaction forces, COP and time using WBB on STS and gait in healthy adults. Methods: Fifteen healthy participants performed three trials of STS and gait on WBB. The time (s), vertical peak (%) and COP path-length (cm) were measured on both tasks. Additionally, counter (%), different peak (%), symmetry ratio, COP x-range and COP y-range were analyzed on STS, 1st peak (%), 2nd peak (%) of weight were analyzed on gait. Intra-class correlation coefficient (ICC), standard error measurement (SEM) and smallest real difference (SRD) were analyzed for test-retest reliability. Results: ICC of all variables except COP path-length appeared to .676~.946 on STS, and to .723~.901 on gait. SEM and SRD of all variables excepting COP path-length appeared .227~8.886, .033~24.575 on STS. SEM and SRD excepting COP path-length appeared about .019~3.933, .054~11.879 on gait. Conclusion: WBB is not only cheaper than force plate, but also easier to use clinically. WBB is considered as an adequate equipment for measuring changes of weight bearing during balance, STS and gait test which are normally used for functional assessment in patients with neurological problems and elderly. The further study is needed concurrent validity on neurological patients, elderly patients using force plate and WBB.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.469-479
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• 2015

Purpose: The purpose of this study is to explore the effect of nursing intervention of aromatherapy hand massage. Method: In order to conduct a meta-analysis, a total of 124 studies were retrieved. From these studies, fifteen studies met the inclusion criteria with a total of 733 participants. And these studies published from January 2004 to July 2013 were included in the journal articles published in Korea. Results: In fifteen studies, Random effect model for the aromatherapy hand massage that 95% confidence level, significant level of p-valve on less than 0.001. Standardized Mean Difference reported systolic blood pressure(d=-9.5320), diastolic pressure(d=-8.8730), pulse(d=-9.1241), anxiety(d=-0.1469), and depression(d=-0.4489) All measurement variables were significantly decreased in the negative direction. Conclusion: This study suggests that aromatherapy hand massage can reduce the level of blood pressure(systolic, diastolic), pulse, anxiety and depression.

• The Journal of the Convergence on Culture Technology
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• v.4 no.1
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• pp.1-6
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• 2018

With the increase of the elderly population, problem on social isolation and loneliness have grown in Korea. Elderly dwelling issues have also been gaining increased attention since dwelling environment is discussed in conjunction with elderly's health and life quality. In this study, the data was collected retrospectively of 350 elderlies who live as single households during 1 September, 2017 to 30 September to identify how to define and measure dwelling depression. The content validity and reliability were evaluated and the correlation between the depression and the dwelling satisfaction were compared. Lastly, a regression analysis on the classification of the dwelling depression was performed. The results show that depression appearing in elderly are more likely to experience a dwelling unsatisfaction. Our results contribute to an understanding and measurement of the dwelling depression which has not been sufficiently specified.