• Journal of Intelligence and Information Systems
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• v.19 no.1
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• pp.1-17
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• 2013

In this article, several types of hybrid forecasting models are suggested. In particular, hybrid models using the generalized additive model (GAM) are newly suggested as an alternative to those using neural networks (NN). The prediction performances of various hybrid and non-hybrid models are evaluated using simulated time series data. Five different types of seasonal time series data related to an additive or multiplicative trend are generated over different levels of noise, and applied to the forecasting evaluation. For the simulated data with only seasonality, the autoregressive (AR) model and the hybrid AR-AR model performed equivalently very well. On the other hand, if the time series data employed a trend, the SARIMA model and some hybrid SARIMA models equivalently outperformed the others. In the comparison of GAMs and NNs, regarding the seasonal additive trend data, the SARIMA-GAM evenly performed well across the full range of noise variation, whereas the SARIMA-NN showed good performance only when the noise level was trivial.

• Journal of People, Plants, and Environment
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• v.24 no.6
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• pp.563-572
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• 2021

Background and objective: The ongoing COVID-19 pandemic restricted daily life, forcing people to spend time indoors. With the growing interest in mental health issues and residential environments, 'pet plants' have been receiving attention during the unprecedented social distancing measures. This study aims to analyze the change in trends of pet plants before and during the COVID-19 pandemic and provide basic data for studies related to pet plants and directions of future development. Methods: A total of 2,016 news articles using the keyword 'pet plants' were collected on Naver News from January 1, 2018 to August 15, 2019 (609 articles) and January 1, 2020 to August 15, 2021 (1,407 articles). The texts were tokenized into words using KoNLPy package, ultimately coming up with 63,597 words. The analyses included frequency of keywords and topic modeling based on Latent Dirichlet Allocation (LDA) to identify the inherent meanings of related words and each topic. Results: Topic modeling generated three topics in each period (before and during the COVID-19), and the results showed that pet plants in daily life have become the object of 'emotional support' and 'healing' during social distancing. In particular, pet plants, which had been distributed as a solution to prevent solitary deaths and depression among seniors living alone, are now expanded to help resolve the social isolation of the general public suffering from COVID-19. The new term 'plant butler' became a new trend, and there was a change in the trend in which people shared their hobbies and information about pet plants and communicated with others in online. Conclusion: Based on these findings, the trend data of pet plants before and after the outbreak of COVID-19 can provide the basis for activating research on pet plants and setting the direction for development of related industries considering the continuous popularity and trend of indoor gardening and green hobby.

• Journal of the Korea Safety Management & Science
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• v.15 no.3
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• pp.163-170
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• 2013

There are many pros and cons for whether smart glasses and watch would be further going technology or not beyond smart phone. What have to do domestically is to find acting ways to catch up with technological gap in short term basis through analyses and investigations in technological issues, patents profile, market forecast. In this paper, firstly we investigate and review technological issues and form factors of smart glasses and HMD, and secondly analyze technological tendency and identify their core technology and intension from global key player's patents analyses connected with smart glasses, and conclusively suggest technological prospects and it's countermeasures.

• Geomechanics and Engineering
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• v.8 no.4
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• pp.595-613
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• 2015

An experimental investigation into the uplift capacity of horizontal square plate anchors in sand with and without geogrid reinforcement is reported. The parameters investigated are the effect of the depth of the single layer of geogrid, vertical spacing of geogrid layers, number of geogrid layers, length of geogrid layers, the effects of embedment depth, and relative density of sand. A series of three dimensional finite element analyses model was established and confirmed to be effective in capturing the behaviour of plate anchor-reinforced sand by comparing its predictions with experimental results. The results showed that the geogrid reinforcement had a considerable effect on the uplift capacity of horizontal square plate anchors in sand. The improvement in uplift capacity was found to be strongly dependent on the embedment depth and relative density of sand. A satisfactory agreement between the experimental and numerical results on general trend of behaviour and optimum geometry of reinforcement placement is observed. Based on the model test results and the finite element analyses, optimum values of the geogrid parameters for maximum reinforcing effect are discussed and suggested.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.137-143
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• 2008

Thermal fatigue life prediction for solder joints becomes the most critical issue in present microelectronic packaging industry. And lead-free solder is quickly becoming a reality in electronic manufacturing fields. This trend requires life prediction models for new solder alloy systems. This paper describes the life prediction models for SnAgCu and SnPb solder joints, based upon non-linear finite element analysis (FEA). In case of analyses of the SnAgCu solder joints, two kinds of shapes are used. As a result, it is found that the SnAgCu solder has longer fatigue life than the SnPb solder in temperature cycling analyses.

• Economic and Environmental Geology
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• v.11 no.1
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• pp.1-9
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• 1978

The study is on petrology and petrochemistry of Pajoo Acidic Igneous pluton which intruded into Precambrian metasediments of basement of the area. The geologic sequence of studied area was shown in table 1 and 10 modal analyses and 7 chemical analyses on the rock samples taken from the body. Pajoo Acidic Igneous rock consist of hypersthene-quartz-diorite and porphyritic adamellite which based on the classification of the subcommision on systematics of igneous rocks of IUGS. And porphyritic adamellite which occured as a small stock was intruded into hypersthene quartz diorite. The rock forming minerals of hypersthene quartz diorite are composed of plagioclase, perthite, quartz, hypersthene, hornblende, biotite and porphyritic adamellite is composed of perthite, quartz, plagioclase and biotite. And the former is hypidiomorphic granular texture and later is porphyritic texture with microcline phenocrysts. In silica-oxides variation diagram, the Pajoo acidic igneous rocks are similar to the trend of Daly's average composition and equivalent to the calc-alkalic rock series. In AMF diagram, these rocks are stock of fissure filling vein type by cooling in magmatic differentiation.

• 한국IT서비스학회:학술대회논문집
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• 2006.11a
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• pp.97-102
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• 2006

정보시스템의 효율적 도입 및 운영 등에 관한 법률이 2005년 12월 고시됨에 따라, 우리 군은 국방부를 중심으로 EA 도입과 적용을 위한 준비 단계에 있다. 본고에서는 미군의 EA 도입사례와 한국군의 EA 추진 현황을 조사하고, 국방 EA의 단계적 도입을 위한 발전방향을 모색하였다. 미군은 4개의 임무영역으로 나누어 EA를 구축하고 있다. 우리 군도 2002년부터 추진해 온 아키텍처 관련 노력을 발전시켜 조직간 업무분장, 범정부 산출물과 국방부 산출물간의 관계 등이 개선이 필요하며, 무엇보다도 최고의사결정자의 관심과 지원을 통해 국방 EA를 추진하여야 할 것이다.

• Journal of Construction Engineering and Project Management
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• v.5 no.3
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• pp.18-28
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• 2015

Bidding and contract systems are used for public construction projects to select contractors following fair competition principles and to execute national budgets effectively. Many challenges have arisen due to a lack of transparency and fairness and because bidding practices have been luck-based. Few comprehensive or comparative analyses have been conducted on the performance and limitations of bidding and contract systems, and empirical analyses designed to improve policies on and the practice of such systems are lacking. This study empirically analyzed current bidding and contract systems to seek ways of improving them. The study proposes several alternatives to resolve the problems with and irrationalities of the current system: 1) improving bidding and selection systems by changing them from a luck-based price competition into a technical merit- and value-based competition; 2) improving the assessment criteria to meet the current market level of bid and winning prices; 3) adjusting contractual responsibilities and sharing structures to meet the current trend; and 4) strengthening the competitiveness and expanding the social responsibility-based procurement systems of construction companies.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.278-291
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• 2016

This study examined research trends via network analyses of keywords appeared in academic research articles about news reports in South Korea during the last 10 years from 2006 to 2015. Keyword network analyses of 4410 keywords from 1108 articles suggested that framing, agenda setting, third-person effect, selective exposure, and uses and gratification were main theories but most studies used framing theory. Research areas included news reports on politics, economics, science, world issues, or tour. However, research on news reports covering culture, sports or daily life were not identified. In terms of media, research on both traditional and emerging media were ample. Research on broadcasting new, online news, and social media were frequently observed.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3109-3112
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• 2012

Background: Many studies have focused on possible associations between the glutathione S-transferase M 1 (GSTM1) null genotype and risk of renal cell carcinoma (RCC), but the impact remains unclear owing to obvious inconsistencies among the findings. The present study aimed to quantify the strength of any association in a meta-analysis. Methods: We searched the PubMed, Embase and CBM databases for studies concerning the association between the GSTM1 null genotype and risk of RCC. We estimated the summary odds ratio (OR) with its 95% confidence intervals (95% CI) to assess the association. Results: The meta-analysis showed the GSTM1 null genotype was not associated with risk of RCC overall (OR = 1.04, 95% CI 0.92-1.18, P = 0.501). For Caucasians, the GSTM1 null genotype was also not associated with risk of RCC (OR=1.02, 95% CI 0.90-1.16, P = 0.761). The cumulative meta-analyses showed a trend of no obvious association between GSTM1 null genotype and risk of RCC as information accumulated. Sensitivity analyses by omitting those studies also did not materially alter the overall combined ORs. No evidence of publication bias was observed. Conclusion: Meta-analyses of available data show that the GSTM1 null genotype is not significantly associated with risk of renal cell carcinoma.