• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.1007-1018
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• 2009

Hydrocyclone is widely used in industry, because of its simplicity in design, high capacity, low maintenance and operational cost. The separation action of a hydrocyclone treating particulate slurry is a consequence of the swirling flow that produces a centrifugal force on the fluid and suspended particles. In spite of hydrocyclone have many advantage, the application for treatment of urban stormwater case study were rare. We conducted a laboratory scale study on treatable potential of micro particles using hydrocyclone filter (HCF) that was a combined modified hydrocyclone with perlite filter cartridge. Since it was not easy to use actual storm water in the scaled-down hydraulic model investigations, it was necessary to reproduce ranges of particles sizes with synthetic materials. The synthesized storm runoff was made with water and addition of particles; ion exchange resin, road sediment, commercial area manhole sediment, and silica gel particles. Experimental studies have been carried out about the particle separation performance of HCF-open system and HCF-closed system. The principal structural differences of these HCFs are underflow zone structure and vortex finder. HCF was made of acryl resin with 120 mm of diameter hydrocyclone and 250 mm of diameter filter chamber and overall height of 800 mm. To determine the removal efficiency for various influent concentrations of suspended solids (SS) and chemical oxygen demand (COD), tests were performed with different operational conditions. The operated maximum of surface loading rate was about 700 $m^3/m^2$/day for HCF-open system, and 1,200 $m^3/m^2$/day for HCF-closed system. It was found that particle removal efficiency for the HCF-closed system is better than the HCF-open system under same surface loading rate. Results showed that SS removal efficiency with the HCF-closed system improved by about 8~20% compared with HCF-open system. The average removal efficiency difference for HCF-closed system between measurement and CFD particle tracking simulation was about 4%.

• Journal of Distribution Science
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• v.9 no.2
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• pp.31-36
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• 2011

I conducted empirical analyses of what happens when an offline channel expands to an online channel and whether the pre-existing offline channel's competitive assets (e.g. brand reputation and level of service satisfaction) can be linked to online channel preference. I found that an offline channel's brand reputation and level of service satisfaction can have a direct influence on offline channel preference and a second-hand influence on online channel preference. Thus, if the competitiveness of the online channel is strong enough and its customers have a higher preference for the offline channel, they will be committed and loyal to the company. The resultant enhanced competitiveness of the offline channel will present opportunities for both present and future success. The main results are the following. First, the management of the distribution channel service quality is more important than that of the brand reputation. Customers' experiences of service and subjective evaluations are not important only as the leading factors in the long-term brand reputation management but also as influential factors in channel preference. SoThus, given that the service quality of the pre-existing channel is not the customers' main concern, a strategy of improving the level of service satisfaction aimed at present customers is more valuable than a wide brand positioning strategy aimed at general and new customers. Second, when an offline channel company establishes an internet shopping mall on an online channel, it is highly likely that the preference and subjective evaluation of the present customers will influence the online channel. This applies not only to the special case of an expansion from an offline intermediary channel to an online one, but also to an online channel acting as an expansion of the business model of a conventional manufacturing or service company: both cases are vertical integrations of marketing channels in an expansion of the distribution channel. My theory applies to a wide range of contexts. Third and finally, any business strategy can grasp the meaning of 'channel expansion. Fundamentally, it is an expansion of the sales activity channel and marketing activity. However, it is also a way of enhancing marketing and sales competitiveness through an expansion to an online or offline channel. The expansion of an offline company to an online channel could be seen not as improvement but as an innovation of the business process by which two goals are achieved with one technique. The former is expected to increase the sales of the offline company, and the latter is also expected to increase sales while also contributing to cost reduction.

• Journal of Intelligence and Information Systems
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• v.26 no.1
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• pp.23-45
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• 2020

Big data is creating in a wide variety of fields such as medical care, manufacturing, logistics, sales site, SNS, and the dataset characteristics are also diverse. In order to secure the competitiveness of companies, it is necessary to improve decision-making capacity using a classification algorithm. However, most of them do not have sufficient knowledge on what kind of classification algorithm is appropriate for a specific problem area. In other words, determining which classification algorithm is appropriate depending on the characteristics of the dataset was has been a task that required expertise and effort. This is because the relationship between the characteristics of datasets (called meta-features) and the performance of classification algorithms has not been fully understood. Moreover, there has been little research on meta-features reflecting the characteristics of multi-class. Therefore, the purpose of this study is to empirically analyze whether meta-features of multi-class datasets have a significant effect on the performance of classification algorithms. In this study, meta-features of multi-class datasets were identified into two factors, (the data structure and the data complexity,) and seven representative meta-features were selected. Among those, we included the Herfindahl-Hirschman Index (HHI), originally a market concentration measurement index, in the meta-features to replace IR(Imbalanced Ratio). Also, we developed a new index called Reverse ReLU Silhouette Score into the meta-feature set. Among the UCI Machine Learning Repository data, six representative datasets (Balance Scale, PageBlocks, Car Evaluation, User Knowledge-Modeling, Wine Quality(red), Contraceptive Method Choice) were selected. The class of each dataset was classified by using the classification algorithms (KNN, Logistic Regression, Nave Bayes, Random Forest, and SVM) selected in the study. For each dataset, we applied 10-fold cross validation method. 10% to 100% oversampling method is applied for each fold and meta-features of the dataset is measured. The meta-features selected are HHI, Number of Classes, Number of Features, Entropy, Reverse ReLU Silhouette Score, Nonlinearity of Linear Classifier, Hub Score. F1-score was selected as the dependent variable. As a result, the results of this study showed that the six meta-features including Reverse ReLU Silhouette Score and HHI proposed in this study have a significant effect on the classification performance. (1) The meta-features HHI proposed in this study was significant in the classification performance. (2) The number of variables has a significant effect on the classification performance, unlike the number of classes, but it has a positive effect. (3) The number of classes has a negative effect on the performance of classification. (4) Entropy has a significant effect on the performance of classification. (5) The Reverse ReLU Silhouette Score also significantly affects the classification performance at a significant level of 0.01. (6) The nonlinearity of linear classifiers has a significant negative effect on classification performance. In addition, the results of the analysis by the classification algorithms were also consistent. In the regression analysis by classification algorithm, Naïve Bayes algorithm does not have a significant effect on the number of variables unlike other classification algorithms. This study has two theoretical contributions: (1) two new meta-features (HHI, Reverse ReLU Silhouette score) was proved to be significant. (2) The effects of data characteristics on the performance of classification were investigated using meta-features. The practical contribution points (1) can be utilized in the development of classification algorithm recommendation system according to the characteristics of datasets. (2) Many data scientists are often testing by adjusting the parameters of the algorithm to find the optimal algorithm for the situation because the characteristics of the data are different. In this process, excessive waste of resources occurs due to hardware, cost, time, and manpower. This study is expected to be useful for machine learning, data mining researchers, practitioners, and machine learning-based system developers. The composition of this study consists of introduction, related research, research model, experiment, conclusion and discussion.

• Korean Security Journal
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• no.44
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• pp.7-35
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• 2015

The objective of this article is to inform and document the contemporary development of the private security industry in Queensland Australia, a premier holiday destination that provide entertainment for the larger region. The purpose of this review is to examine the comtemporary development of mandated licensing regimes regulating the industry, and the necessary reform agenda. The overall aim is threefold: first, to chart the main outcomes of the two-wave of reforms since the mid-'90s; second, to examine the effectiveness of changes in modes of regulation; and third, to identify the criteria that can be considered a best practice based on Button(2012) and Prenzler and Sarre's(2014) criteria. The survey of the Queensland regulatory regime has demonstrated that, despite the federal-guided reforms, there remain key areas where further initiatives remain pending, markedly case-by-case utilisation of more proactive strategies such as on-site alcohol/drug testing, psychological evaluations, and checks on close associates; lack of binding training arrangement for technical services providers; and targeted auditing of licensed premises and the vicinity of venues by the Office of Fair Trading, a licensing authority. The study has highlighted the need for more determined responses and active engagements in these priority areas. This study of the development of the licensing regimes in Queensland Australia provides useful insights for other jurisdictions including South Korea on how to better manage licensing system, including the measures required to assure an adequate level of professional competence in the industry. It should be noted that implementing a consistency in delivery mode and assessment in training was the strategic imperative for the Australian authority to intervene in the industry as part of stimulating police-private partnerships. Of particular note, competency elements have conventionally been given a low priority in South Korea, as exemplified through the lack of government-sponsored certificate; this is an area South Korean policymakers must assume an active role in implementing accredited scheme, via consulting transnational templates, including Australian qualifications framework.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.3
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• pp.249-257
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• 2007

State of problem : The use of zirconium oxide all-ceramic material provides several advantages, including a high flexural strength(>1000MPa) and desirable optical properties, such as shading adaptation to the basic shades and a reduction in the layer thickness. Along with the strength of the materials, the cementation technique is also important to the clinical success of a restoration. Nevertheless, little information is available on the effect of different surface treatments on the bonding of zirconium high-crystalline ceramics and resin luting agents. Purpose : The aim of this study was to test the effects of surface treatments of zirconium on shear bond strengths between bovine teeth and a zirconia ceramic and evaluate differences among cements Material and methods : 54 sound bovine teeth extracted within a 1 months, were used. They were frozen in distilled water. These were rinsed by tap water to confirm that no granulation tissues have left. These were kept refrigerated at $4^{\circ}C$ until tested. Each tooth was placed horizontally at a plastic cylinder (diameter 20mm), and embedded in epoxy resin. Teeth were sectioned with diamond burs to expose dentin and grinded with #600 silicon carbide paper. To make sure there was no enamel left, each was observed under an optical microscope. 54 prefabricated zirconium oxide ceramic copings(Lava, 3M ESPE, USA) were assigned into 3 groups ; control, airborne-abraded with $110{\mu}m$ $Al_2O_3$ and scratched with diamond burs at 4 directions. They were cemented with a seating force of 10 ㎏ per tooth, using resin luting cement(Panavia $F^{(R)}$), resin cement(Superbond $C&B^{(R)}$), and resin modified GI cement(Rely X $Luting^{(R)}$). Those were thermocycled at $5^{\circ}C$ and $55^{\circ}C$ for 5000 cycles with a 30 second dwell time, and then shear bond strength was determined in a universal test machine(Model 4200, Instron Co., Canton, USA). The crosshead speed was 1 mm/min. The result was analyzed with one-way analysis of variance(ANOVA) and the Tukey test at a significance level of P<0.05. Results : Superbond $C&B^{(R)}$ at scratching with diamond burs showed the highest shear bond strength than others (p<.05). For Panavia $F^{(R)}$, groups of scratching and sandblasting showed significantly higher shear bond strength than control group(p<.05). For Rely X $Luting^{(R)}$, only between scratching & control group, significantly different shear bond strength was observed(p<.05). Conclusion : Within the limitation of this study, Superbond $C&B^{(R)}$ showed clinically acceptable shear bond between bovine teeth & zirconia ceramics regardless of surface treatments. For the surface treatment, scratching increased shear bond strength. Increase of shear bond strength by sandblasting with $110{\mu}m$ $Al_2O_3$ was not statistically different.

• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.390-397
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• 2013

The study, utilizing a data envelopment analysis (DEA) which is one of the nonparametric estimation methods, aims to evaluate the management efficiency of chestnut tree cultivators in such provinces in Chungchungnam-do as Cheong-yang, Gong-ju, Bu-yeo and so on. The analysis data of this study is based on inputs and outputs of 20 forestry households surveyed in the 2012 survey titled 'A Study on Current Level and Condition of Chestnut Cultivation and Management', which was conducted from March 2012 to October 2012. The elements of inputs are composed of management cost, harvesting cost, material cost, non-operation expenses and cultivation area, while the element of output is a gross margin only. Then the study analyzes a technical efficiency, a puretechnical efficiency and a scale efficiency using CCR and BCC model among DEA methods. Based on that, it also provides improvement methods for forestry households that turned out to be inefficient. In order to verify the result of DEA analysis, the study additionally compares a result of this efficiency study with that of chestnuts management standard diagnostic table. According to the result, the average value of technical efficiency analyzed was 0.667, proving to be inefficient in general. Given that the average value of pure-technical efficiency was 0.944 and that of scale efficiency was 0.703, it can be inferred that inefficiency exists in the field of scale, not in the field of cultivation techniques. As for forestry households with the efficiency score of 1, it is shown that there were 6 households that recorded 1 in the technical efficiency field and 13 households that recorded 1 in the pure technical efficiency. Meanwhile, there were 6 households that recorded 1 in all of the three aspects. In the comparison with the scores from chestnuts management standard diagnostic table, there were 5 households made a high score of over 80, among which are 3 households with score 1 in the technical efficiency. Also, the results of this study and the chestnuts management standard diagnostic table are proved to have the same result, both of them showing the same households that recorded the highest score and the lowest score. This means the management efficiency evaluation using DEA can be applied to the fieldwork along with the chestnuts management standard diagnostic table.

• The Journal of Korean Institute for Practical Engineering Education
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• v.3 no.1
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• pp.1-8
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• 2011

In this paper, as a new educational cooperation model, seeking the problems and the directions of progress on GPOE(Gyeonggi Provincial Office of Education)'s innovational education district project, recognizing the various points of issue of SVHS(specialized vocational high schools) faced now, suggesting the contents and standards of the program as measures of enhancing competitiveness of SVHS, analyzing the strengths and weaknesses of project of innovational education district and finding the plans for progress. According to the result of the advanced study and analysis, it shows that the aid as well as the supporting object of helping the SVHS's students find a job don't reach a certain level. As the aid supports across the general elementary and secondary schools, it tends to show much more emotional software-based support required by elementary school, middle school and general high school as universal education welfare rather than hardware-based support required by SVHS. Despite the competent evaluation on the survey about the supporting method from SVHS's parents teachers and students, the survey includes that teachers who ask the balancing support are increasing, some students suspect its effect of education and some parents as a residential position ask the regional growth rather than education So there are a lot of confusions among the teachers, students and parents yet. To overcome these problems, we ensure the internal stability of local education community and GPOE and local government get out large scale constructions with trust and belief to make a revolution of public education in supporting the administrative task and finance and to accomplish the program that best suits our SVHS's state to be supported without dividing educational software and hardware, should reflect the demand of field by for expert group being built and attended when build the local revolution community. Also plan to make full use of local human and property infrastructure should be added. To this end, as programs to build a pool of guest lecturers are provided to teachers who carry out innovative education programs, we seek the reformations to give students opportunities to widen participation in other school programs.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.6
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• pp.46-58
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• 1999

The purpose of this research was to find out the state of the nursing performance of the home care nurses in Seoul in order to provide the data for the practical work guide. The data were collected from fifty home care nurses working in 22 institutions located in Seoul. The research tool used for this research was modified and tested by Song Jong-Rye(1999) which was originally modified the standard tool of American Nurses Association (1998) and was partly supplement and adjusted for this research. The reliability of this tool was Cronbach's $\alpha$=.0982. The collected data were statistically processed using SAS for t-test, ANOVA. $Scheff\'{e}$ test. Among the surveyees, 50% have been working as a home care nurse more than three years and 74.0% of them were married. And 52% have B.S degree with certification of home care nurse from the certification program for Home Care Nurses affiliated at nursing schools. Half of the home care nursing organizations were based on the general hospitals, and most(78%) of the responsible senior personnels of those organizations were nurses. The following results are drawn from this research. 1) The level of nursing performance by the task sectors General performance level of home care nurses was relatively high in grade of 3.06 from total 4.00. Among the task sectors. the ethical field scored the highest points, and the next were nursing intervention, professional training, and data gathering, and the research sector scored the lowest point. 2) The level of nursing performance by general features of home care nurses Statistically relevant correlation between performance according to the duration of working experience as a nurse(p=0.8951) and performance according to the duration of working as home care nurse(p=0.2263) did not emerge. Also, performance by marriage status(p=0.2218), education(p=0.5733), and taking the certification program for home card nurse(p =0.1560) has no statistically meaningful correlation. 3) The level of nursing performance by the type of home care nursing organizations There exists a significant difference(p=0.002) between performances by the types of organizations. Most of the responsible senior personnels of the home care nursing organization were nurses. The level of nursing performance of the home care nursing organization under nurse management was relatively higher than that of home care nursing organizations led by medical doctors or non-medical professional, but this was not proved as statistically meaningful(p =0.3617). 4) The level of nursing performance by task sectors according to the characteristic of home care nursing service organization There exists a significant difference between nursing performances by task sectors according to the characteristics of home care nursing organization(p=0.002). In case of model research center of one College of Nursing, the nursing performance in the sectors of organization, theory, and data gathering were lower than that of in hospital based home care nursing service. And in case of local home care centers, performances in sectors of organization, theory, data gathering, nursing intervention. professional training, and research sectors were significantly low. Based on the obtained results, overall performance of home care nurses can be appraised as relatively good. Especially, performances in sectors of the nursing intervention, nursing plan. and data gathering including the in direct nursing were recorded high scores. From this, it can be concluded that high quality of nursing is relatively practicing for home patients at these days. Since the high quality of nursing for patients was directly related to the level of nursing performances of home care nurses, it is required to improve practical performance level of them by making constant evaluation and running continual education program and supplementing curriculum for the sectors with low scores.

• Journal of the Korean earth science society
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• v.24 no.5
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• pp.378-392
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• 2003

The purpose of this study is to investigate the depth of earth science teachers' concern over the 7th Science Curriculum and levels of their use of it in reality, using the tools "Concern" and "Levels of use" which are two important tools use in CBAM. The results of the study are as follows. How much concern do the earth science teachers have over the 7th Science Curriculum? There are seven stages (from 0 stage to 6 stage) of teachers' concern over the curriculum. o stage represents teachers' indifference to the curriculum and 98% teachers are placed in this stage. According to the study on teachers' teaching experience, teachers having from 10 to 14 years of teaching experience are the most indifferent to the 7th Science Curriculum, compared to other teachers. Which levels of use of the 7th science curriculum do earth science teachers choose in reality? There are five levels of use (from 1 to 5) of the 7th curriculum. 43.97% of teachers are placed in the 3rd level called "Mechanical level", which represents a teacher-concerned learning method with consideration of learners' response. According to the study on teachers' frequency of level of use in the fields of "Instruction objects, Instruction contents, Instruction methods, Instruction materials and Evaluation.", teachers chose high levels of use in the fields of "Instruction objects and Instruction contents" and low levels of use in the other three fields. What factors are barriers for earth science teachers to perform the 7th Science Curriculum in reality? 80.9% of teachers have trouble performing the 7th Science Curriculum in reality because of too much routine work, official papers, and lack of instructional materials, laboratories, training systems and workshops. The two biggest barriers among the above are routine work and of official papers. According to the study on teachers' teaching experience, teachers having from 0 to years of teaching experience have the most trouble in performing the curriculum in reality, compared to other teachers.

• Journal of Radiation Protection and Research
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• v.40 no.3
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• pp.124-131
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• 2015

Radiation exposure to humans can be caused by the gamma rays emitted from natural radioactive elements(such as uranium, thorium and potassium and any of their decay products) of Naturally Occurring Radioactive Materials(NORM) or Technologically Enhanced Naturally Occurring Radioactive Materials(TENORM) added consumer products. In this study, assume that activity of radioactive elements is $^{238}U$, $^{235}U$, $^{232}Th$ $1Bq{\cdot}g^{-1}$, $^{40}K$ $10Bq{\cdot}g^{-1}$ and the gamma rays emitted from these natural radioactive elements radioactive equilibrium state. In this study, reflected End-User circumstances and evaluated annual exposure dose for products based on ICRP reference voxel phantoms and ICRP Recommendation 103 using the Monte Carlo Method. The consumer products classified according to the adhere to the skin(bracelet, necklace, belt-wrist, belt-ankle, belt-knee, moxa stone) or not(gypsum board, anion wallpaper, anion paint), and Geometric Modeling was reflected in Republic of Korea "Residential Living Trend-distributions and Design Guidelines For Common Types of Household.", was designed the Room model($3m{\times}4m{\times}2.8m$, a closed room, conservatively) and the ICRP reference phantom's 3D segmentation and modeling. The end-user's usage time assume that "Development and Application of Korean Exposure Factors." or conservatively 24 hours; in case of unknown. In this study, the results of the effective dose were 0.00003 ~ 0.47636 mSv per year and were confirmed the meaning of necessary for geometric modeling to ICRP reference phantoms through the equivalent dose rate of belt products.