• The Journal of Korean Medicine
• /
• v.30 no.3
• /
• pp.1-14
• /
• 2009

Objectives : Alzheimer's disease (AD) is characterized by neuronal loss and extracellular senile plaque. Moreover, the cellular actions of ${\beta}$-amyloid (A${\beta}$ play a causative role in the pathogenesis of AD. This study was designed to determine whether Woo-Gui-Um, a commonly used Korean herbal medicine, has the ability to protect cortical and hippocampal neurons against A${\beta}_{25-35}$ neurotoxicity Methods : In the present study, the authors investigated the preventative effects of the water extract of Woo-Gui-Um in a mouse model of AD. Memory impairment was induced by intraventricularly (i.c.v.) injecting A${\beta}_{25-35}$ peptides into mice. Woo-Gui-Um extract was then administered orally (p.o.) for 14 days. In addition, A${\beta}_{25-35}$ toxicity on the hippocampus was assessed immunohistochemically, by staining for Tau, MAP2, TUNEL, and Bax, and by performing an in vitro study in PC12 cells. Results : Woo-Gui-Um extract had an effect to improve learning ability and memory score in the water maze task. Woo-Gui-Um extract had significant neuroprotective effects in vivo against oxidative damage and apoptotic cell death of hippocampal neurons caused by i.c.v. A${\beta}_{25-35}$. In addition, Woo-Gui-Um extract was found to have a protective effect on A${\beta}_{25-35}$-induced apoptosis, and to promote neurite outgrowth of nerve growth factor (NGF)-differentiated PC12 cells. Conclusions : These results suggest that Woo-Gui-Um extract reduces memory impairment and Alzheimer's dementia via an anti-apoptotic effect and by regulating Tau and MAP2 in the hippocampus.

• Journal of KIISE:Computing Practices and Letters
• /
• v.14 no.2
• /
• pp.130-142
• /
• 2008

Different from other ontology languages, TopicMap is capable of integrating numerous amount of heterogenous information resources using the locational information without any information transformation. Although many conventional editors have been developed for topic maps, they are standalone-type only for writing XTM documents. As a result, these tools request too much time for handling large-scale data and provoke practical problems to integrate with legacy systems which are mostly based on relational database. In this paper, we model a large-scale topic map structure based on XTM 1.0 into RDB structure to minimize the processing time and build up the ontology in legacy systems. We implement a topic map platform called X-TOP that can enhance the efficiency of ontology construction and provide interoperability between XTM documents and database. Moreover, we can use conventional SQL tools and other application development tools for topic map construction in X-TOP. The X-TOP is implemented to have 3-tier architecture to support flexible user interfaces and diverse DBMS. This paper shows the usability of X-TOP by means of the comparison with conventional tools and the application to healthcare cancer ontology management.

• Journal of Astronomy and Space Sciences
• /
• v.17 no.1
• /
• pp.53-66
• /
• 2000

We developed low light CCD imaging system using thermoelectric cooling method collaboration with a company to design a commercial model. It consists of Kodak KAF-0401E(768$\times$512 pixels) CCD chip, thermoelectric module manufactured by Thermotek. This TEC system can reach an operative temperature of $-25^{\circ}C$. We employed an Uniblitz VS25s shutter and it has capability a minimum exposure time 80ms. The system components are an interface card using a Korea Astronomy Observatory (hereafter KAO) ISA bus controller, image acquisition with AD9816 chip, that is 12bit video processor. The performance test with this imaging system showed good operation within the initial specification of our design. It shows a dark current less than 0.4e-/pixel/sec at a temperature of $-10^{\circ}C$, a linearity 99.9$\pm$0.1%, gain 4.24e-/adu, and system noise is 25.3e-(rms). For low temperature CCD operation, we designed a TEC, which uses a one-stage peltier module and forced air heat exchanger. This TEC imaging system enables accurate photometry($\pm$0.01mag) even though the CCD is not at 'conventional' cryogenic temperatures(140k). The system can be a useful instrument for any other imaging applications. Finally, with this system, we obtained several images of astronomical objects for system performance tests.

• Journal of Distribution Science
• /
• v.18 no.5
• /
• pp.99-109
• /
• 2020

Purpose: This study aims to develop and empirically analyze a research model in order to comprehend the relationship among the service quality of market-wholesaler system, re-transaction intention, and recommendation intention of forwarder. Further, we suggest new six factors reflecting the service quality of market-wholesaler system and highlight market expansion of forwarder as a mechanism in the relationship. Research design, data and methodology: The authors developed the new scales measuring the service quality of market-wholesaler system (i.e. trade price, price fluctuation, payment receipt, settlement period, trade information, and customer service) and conducted a cross-sectional survey for 439 forwarders in a wholesale market. And then we performed a series of path analyses to test hypotheses. The hypotheses are as follows. [H1] The service quality of market-wholesaler system will positively affect forwarders' market expansion, [H2] Forwarders' market expansion will positively affect their re-transaction intention, [H3] Forwarders' market expansion will positively affect their recommendation intention, [H4] Forwarders' re-transaction intention will positively affect their recommendation intention. Results: The results showed that all the six factors for the service quality of market-wholesaler system were positively related to market expansion of forwarders. There was a differential effectiveness in the six factors of the service quality. More specifically, the positive effect of customer service factor was the strongest on market expansion of forwarders. And the respective effects of trade price, price fluctuation, settlement period, trade information factors were followed in order. The positive effect of payment receipt factor was the weakest on market expansion of forwarders. Also, market expansion of forwarders was positively related to their re-transaction intention and recommendation intention. Furthermore, market expansion of forwarders was indirectly related to recommendation intention through re-transaction intention as well. Conclusions: The research findings provide important theoretical and practical implications. This study is the first to attempt to test the perception of forwarders for the service quality of market-wholesaler system by developing and using the new scales. Also, there has been a sharp controversy about the effectiveness of market-wholesaler system. The findings support that market-wholesaler system would be activated by empirically verifying the effectiveness of the service quality on the various outcomes.

• The Journal of the Korea Contents Association
• /
• v.9 no.10
• /
• pp.482-491
• /
• 2009

The purpose of this research is to design and develop teacher assistant contents 'My Class' for an intelligent robot iRobiQ, using in early childhood educational setting. After observing daily activities and correspondence role of teachers in educational settings, we selected the robots' target contents as 6 main functions (Attendance, Activity, Gallery, Learning, Role Calling, and Timer). We designed the contents according to the PLU (Player-Learner-User) model which suggests importance of entertainment, education, and enabling features to meet player, learner, and user requirements. We also considered 'emotional' features to satisfy 'companion' requirements. The developed contents in this study was deployed in kindergarten classrooms consisting of five-years-old for 4 weeks to see how they response and use the contents. We found that both teachers and children were likely to show positive responses to the contents. Especially, young children responded to the entertainment and emotional features more actively than to the other features. And they continually explored for something new inside the contents. Finally, this paper discusses what should be considered to develop more useful teacher assistant contents for iRobiQ.

• Journal of Distribution Science
• /
• v.16 no.10
• /
• pp.65-76
• /
• 2018

Purpose - This paper investigates how the market value of the firms are impacted by distribution information technology investment in Korea over time and across markets, industries and project characteristics. This is the first empirical study on the market payoffs from the RFID investment in Korea. The purpose of this study is to provide a appropriate guideline for investors and practitioners with respect to the announcement representing RFID adoption in Korea. This reaction guideline will stimulate the practitioners to monitor and evaluate the benefits and costs of the innovative RFID technology. Research design, data, and methodology - This paper employs event study methodology to analyze the payoffs from distribution information technology investment announcements over a fifteen-year period from 2003 to 2017. Event study method is based on the assumptions such as market efficiency, unanticipated RFID invest announcements and no confounding effects in the data. This study collected the information on RFID investment announcements by using a full text search engine Bigkinds provided by Korea Press Foundation over a fifteen-year period from January 2003 through December 2017. This paper selected 88 announcements representing RFID adoption by 46 firms. This paper estimated the payoffs from RFID investment announcement through events windows by using the market model of Mcwilliams and Siegel (1997) and calculated the Z-values. Using this test statistics we could infer if RFID adoption make large differences in abnormal returns across various classifications of the firms. Results - There is significant positive market returns from the announcement representing distribution information technology investment in the pre-2009 time period, the significances of payoffs disappear in the post-2009 time period. For this reason investors or practitioners can understand the importance of market entry time and the fact that the greater rewards may belong to early innovators while late imitators cannot reap such a rewards. This paper also find that there is a large differences in the payoffs from the announcement across markets, industries and project characteristics. Conclusions - Analysing the selected sample of 88 announcements representing RFID Adoption over fifteen-year period from 2003 to 2017, this study find that there is not only significant abnormal excess returns from RFID investment announcements but also there is great differences in the abnormal returns over time and across firm sizes or affiliated markets, industries, and project characteristics. This means that there are considerable values for the investors across various firm classifications. The findings of this paper provide useful implications for the practitioners to make judicious decisions whether to adopt the innovative technologies in general or not considering the various concrete circumstances in Korea.

• The Journal of the Korea Contents Association
• /
• v.20 no.9
• /
• pp.29-42
• /
• 2020

The purpose of this study is to present a qualitative research method for extracting and analyzing the comments written by YouTube video users. To do this, we used YouTube users' feedback to measure the hedonic, social, and utilitarian gratification of use and gratification theory(UGT) through by using analysis and topic modeling. The result of the measurement found that the first reason why users watch the trot singer, Cho Myung-sub's video in the KBS Korean broadcasting channel is to achieve hedonic gratification with high frequency. In word-document network analysis, the degree of centrality was high in words, such as 'cheering', 'thank you', 'fighting', and 'best'. Betweenness centrality is similar to the degree of centrality. Eigenvector centrality also shows that words such as 'love', 'heart', and 'thank you' are the most influential words of users' opinions. The results of the centrality analysis present that the majority of video users show their 'love', 'heart' and 'thank you' for the video. it indicates that the high words in centrality analysis is consistent with the high frequency words of hedonic and social gratification dimension of the UGT. The study has research methodological implication that shed light on the motivations for watching YouTube videos with UGT using text mining techniques that automate qualitative analysis, rather than following a survey-based structural equation model.

• Geophysics and Geophysical Exploration
• /
• v.16 no.4
• /
• pp.250-256
• /
• 2013

Using shear wave velocity is more reasonable to estimate strength and integrity of rock compared with using compressional wave. It is often ambiguous to pick the dominant frequency caused by torsional wave when evaluating $V_S$ of rock specimen from FFRC method. It is also sometimes ambiguous to pick the first arrival point of S wave compared with P wave in the signals acquired from ultrasonic velocity method. Otherwise, the procedure of evaluating $V_P$ using ultrasonic velocity method and $V_L$ using FFRC method is relatively stable. Through the relationship between elastic modulus, poisson's ratio and $V_S$ can be obtained from $V_P$, $V_L$. Applicability was checked using model specimens having different material property and length and rock specimens sampled in mine area, and usefulness of proposed procedure was verified.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.1727-1731
• /
• 2008

수자원의 효율적인 관리를 위해서는 신뢰성 있는 유량자료의 획득이 대단히 중요하다. 우리나라는 양질의 유량자료를 획득하기 위해 매년 많은 시간과 돈을 투자하고 있으나 자료의 질적인 면에서 만족할 만한 성과를 얻지 못하고 있다. 현재까지 우리나라의 유량자료는 댐의 수문자료와 수량관리 부처인 건교부에서 운영하는 수위표 지점의 수위-유량곡선에서 산출된 자료에 의존하고 있다. 그러나 수위-유량 관계식을 보정하기 위한 유량측정사업이 지속적이지 못하며, 이 관계식은 유량이 적은 저수기 및 갈수기에는 부정확하다는 한계가 있다. 또한, 국립환경과학원 낙동강물환경연구소에서 오염총량관리를 위한 낙동강수계 유량측정사업을 실시하고 있지만, 목적은 낙동강수계의 오염총량관리 단위유역 말단 47개 지점에서 유량측정을 효율적으로 실시하여 수질정책의 기초자료를 제공하는데 있다. 이 자료 역시 오염총량관리를 위하여 유량측정을 실시하여 수자원의 효율적인 관리를 위한 일 유량을 알 수가 없는 한계점을 가지고 있다. 따라서 저수기 및 갈수기에 수질정책의 기초자료를 제공하기 위해서 하천을 포함한 유역의 정확한 강우-유출특성의 파악이 필요하다. 그러나 강우-유출특성 또한 유역 내 강우의 시 공간적 분포가 다르며 그 자가 비선형성이 강하고 여러 변동성을 포함하므로, 강우로부터 하천의 유출량의 정확한 해석이 불가능하다. 그러나 최근 인공지능 분야에서 신호처리, 지능제어 및 패턴인식 등의 수단으로 사용되고 있는 신경망은 학습이라는 최적화 과정을 통해 입력과 출력으로 구성되는 하나의 시스템을 비선형적으로 구축할 수 있으며 이러한 이점을 활용하여 수자원 분야에서 다양하게 적용되고 있다. 본 연구의 목적은 강우-유출자료 및 댐 방류량 자료의 비선형적인 특정을 가장 잘 반영할 수 있는 신경망모형을 적용하여 수질정책의 기초자료를 제공하기 위하여 신뢰성 있는 유량자료를 산정하는 모형을 개발하는 것이다. 이를 위해서 낙동강물환경연구소에서 오염총량관리를 위한 낙동강수계 유량측정 지점 상류의 댐 방류량의 일 방류량자료와 강우자료를 입력 자료로 하여 유량을 예측할 수 있는 유량예측 신경망 모형 FFBN(Flow Forecasting By Neural)을 개발하였다. 그리고 입력 자료로서 장기유출모형인 SWAT의 모의결과를 입력 자료로 추가한 FFBNS(Flow Forecasting By Neural and SWAT)을 개발하였다. 신경망 모형의 구조는 입력층과 출력층 사이에 하나의 은닉층이 존재하는 다층 신경망으로 구성하였으며, 학습단계에서는 오류 역전파 알고리듬 학습방법 중 모멘텀법을 사용하였다. 예측된 유출량을 실측치와의 비교를 위하여 낙본D지점과 낙본 E지점에 대하여 $2005{\sim}2006$년까지의 모의 결과를 낙동 수위측정지점과 구미 수위측정지점의 실측치 통하여 복잡한 비선형성을 가지는 유출 시계열 자료에 대한 효과적인 최적의 신경망모델을 개발하여 유량을 예측하고 적용 가능성을 검토하고자 한다. 모의 결과는 수질정책의 기초자료 제공에 기여할 수 있을 것으로 판단된다.

• Journal of the Korean Magnetics Society
• /
• v.17 no.2
• /
• pp.86-89
• /
• 2007

[ $FeCr_2Se_4$ ] prepared under the high pressure (3 GPa) has been studied with x-ray, neutron diffraction techniques, superconducting quantum interference device (SQUID) magnetometer, resistance, and Mossbauer spectroscopy. The temperature dependence of resistance is explained by Mott-VRH and small polaron model for the regions I (T<20 K) and II (T>42 K), respectively. Neutron diffraction results show an antiferromagnetic spin-lattice coupling near the Neel temperature. So finally the distance of atom is enlarged in region (110$FeCr_2Se_4$ shows convex type of temperature dependence.