• The Journal of Information Systems
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• v.26 no.3
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• pp.187-209
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• 2017

Purpose The sharing economy is the most important keyword that is changing the paradigm of the world economy and management, and it was selected as one of 10 ideas to change the world in 2011 in Time magazine. The purpose of this study is to verify the structural relationship between perceived value and risk, network effect, usefulness, trust, and intention to use of accommodation service. In addition, the effects of utility and trust, and the experience of using accommodation service are controlled by the effect of empirical value and reciprocal value among the perceived value of sharing economic service, The purpose of this study is to propose a plan to activate the accommodation sharing service. Design/methodology/approach This study was designed to investigate the structural relationship between perceived value, perceived risk, network effect, usefulness, trust, and intention to use. Empirical analysis was done using SPSS 21.0 and AMOS 21.0 Findings Based on the results of this study, the following conclusions can be drawn. First, it was concluded that the higher the economic value of the accommodation sharing service is, the more useful and reliable the service is. Second, the higher the experiential value of the accommodation sharing service is, the higher the usefulness and reliability of the service are. Third, it was concluded that the higher the value of the mutual benefit of the accommodation sharing service is, the higher the trust level of the service is, but not the usefulness of the service. Fourth, it was concluded that the higher the perceived risk of accommodation sharing service is, the lower the service trust level is, but the service usability is not affected. Fifth, it was concluded that the larger the network effect of the accommodation sharing service is, the more useful the service is, but it does not affect the reliability of the service. Sixth, it was concluded that the higher the overall reliability of the accommodation sharing service is, the higher the usefulness of the service is. Seventh, it was concluded that the higher the overall usefulness and reliability of the accommodation sharing service are, the higher the intention to use the sharing service is. Finally, in order to test the effect of the experience on the use of trust and usefulness of the accommodation sharing service, multiple group analysis was conducted to examine the relationship between trust and usefulness, It is shown that there is a moderating effect in the path.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.533-544
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• 2015

Unlike the concrete structure built on land, that exposed to the marine environment is greatly degraded in durability due to the exposure to not only the physical action caused by sea wind, tide, and wave, but also the harsh conditions, including the chemical erosion and freeze-thaw which result from $SO_4{^{2-}}$, $Cl^-$ and $Mg^{2+}$ ions in seawater. In the process of the large scaled construction of submerged concrete structures, of course environmental hazardous substance, such as alkaline (pH) and heavy metals, may be leached. Thus, this issue needs to be adequately reviewed and studied. Therefore, this study attempted to develop a CSA (Calcium Sulfo Aluminate) activator using electric arc furnace reducing slags, as well as the eco-friendly concrete for artificial reefs using electric arc furnace oxidizing slag as aggregate for concrete. The strength properties of the eco-friendly concrete exposed to the marine environment were lower than those of the normal concrete by curing 28 days. This suggest that additional studies are needed to improve the early strength of the eco-friendly concrete. With respect to seawater resistance of the eco-friendly concrete, the average strength loss against 1 year of curing days reached 8-9%. the eco-friendly concrete using high volume of ground granulated blast furnace slags and high specific gravity of electronic arc furnace oxidizing slag demonstrated the sufficient usability as a freeze-thaw resistant material. With respect to heavy metal leaching properties of the eco-friendly concrete, heavy metal substances were immobilized by chemical bonding in the curing process through the hydration of concrete. Thus, heavy metal substances were neither identified at or below environmental hazard criteria nor detected, suggesting that the eco-friendly concrete is safe in terms of leaching of hazardous substances.

• Archives of design research
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• v.15 no.1
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• pp.143-152
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• 2002

As the Internet has been a daily instrument of our lives, the numbers of Internet users are increasing rapidly. Especially, we have to pay special attention to about rapid increasing of juvenile users. In the 1990's, Kids are growing up literally surrounded by new technologies and mu1timedia experiences. For these kids, most of the techno1ologies that we adults find surprising or even incredible are a part of their everyday landscape, a fact of life. Currently, only few of research and discussion has gone into understanding this field. And most of these web sites, set importance on furnishing information only. So educational characters of web are not manifested fully as well as children soon get board with learning with Internet so that feel difficulties in searching and accepting information. At this point, we must try to develop educational sites Not only to show information but also to offer a rich and entertaining time for kids while providing playful teaming and increased technological fluency. Fer this purpose, Web site should be all about combining play with learning. Site navigation should be easy and the pages load quickly. The page download time is also being considerable, which could send kids withy mouse-fingers looking for entertainment elsewhere. Everything about the site must have a familiar feel, uses adequate colors to be satisfied with the juveniles. Multimedia can help the communications in the websites. To maximize the educational effect, technological research and continues invest are need, in addition to usability test.

• Journal of Internet Computing and Services
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• v.12 no.2
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• pp.85-101
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• 2011

The recommender system analyzes users' preference and predicts the users' preference to items in order to recommend various items such as book, movie and music for the users. The collaborative filtering method is used most widely in the recommender system. The method uses rating information of similar users when recommending items for the target users. Performance of the collaborative filtering-based recommendation is lowered when attacker maliciously manipulates the rating information on items. This kind of malicious act on a recommender system is called 'Recommendation Attack'. When the evaluation data that are in continuous change are analyzed in the perspective of data stream, it is possible to predict attack on the recommender system. In this paper, we will suggest the method to detect attack on the recommender system by using the stream trend of the item evaluation in the collaborative filtering-based recommender system. Since the information on item evaluation included in the evaluation data tends to change frequently according to passage of time, the measurement of changes in item evaluation in a fixed period of time can enable detection of attack on the recommender system. The method suggested in this paper is to compare the evaluation stream that is entered continuously with the normal stream trend in the test cycle for attack detection with a view to detecting the abnormal stream trend. The proposed method can enhance operability of the recommender system and re-usability of the evaluation data. The effectiveness of the method was verified in various experiments.

• Korean Journal of Plant Resources
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• v.26 no.4
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• pp.426-432
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• 2013

The results of the content of total polyphenol and flavonoid, DPPH (1-1-diphenyl-2-picryl-hydrazyl) radical scavenging activity, ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)] radical scavenging activity, nitrite scavenging activity and SOD-like activity of methanol extracts from immature cotton boll are follows. The contents of total polyphenol and flavonoid compound were higher in small size cotton boll, and DPPH and ABTS radical scavenging activity also showed a relatively high activity in the small size. These results indicate that there is a correlation between phenol content and DPPH radical scavenging, ABTS radical scavenging. The test concentrations of immature cotton boll extract for measuring DPPH and ABTS radical scavenging activities were set as 1.25, 2.5, 5, 10 and 20 mg/ml. Immature cotton boll has high radical scavenging activity at the concentration of 1.25~20 mg/ml and the result showed a tendency to increase in a concentration-dependent. The nitrite scavenging activity showed high activity in the pH 1.2, and the result in the pH 4.2 showed progressively less active, and in the pH 6.0 near neutral was confirmed that does not affect the nitrite scavenging. In addition, SOD-like activity showed somewhat lower activity compared with ascorbic acid, but tended to be higher when compared with the results of the other natural substances. Through this experiment, we confirmed that immature cotton boll was excellent antioxidant activity. Therefore, it is demonstrated that the cotton suggest the possibility of development of new material for cosmetic product or functional food in the future, and is expected to make a greater usability.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5D
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• pp.473-481
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• 2012

Demand of Natural Gas (NG) consumption is continuously increasing by long service life and low environmental impact than other fossil fuels. Because of this reasons, Gas wells exploration and huge LNG plant construction project are being boosted world-widely. Especially, overseas NG pipe-line projects are emerging by considering safe and efficiency at the inter-country sections. At the same time, Korean contractors are being achieved to record-breaking performance at 2011's overseas construction market and 80% of new-record was attained from overseas plant construction projects. Nevertheless, Korean contractors are behind than overseas leading contractors by geographical distance from gas wells and concentrated demand for storage plant. In these reasons, this paper aims to develop the standardized business process model(BPM) for overseas NG pipe-line project at project planning phase to support the project entry. To this aim, first of all, extract the BPM through the broad literature and overseas construction market review and domestic/overseas pipe-line project analysis. Second, Test-bed was performed to confirm of practical applicability by 4 experts. And then 15 experts survey were performed to validate the usability and effectiveness of BPM for overseas NG pipe-line project. Consequently, if Korean contractors are using this BPM with their own know-how and experiences, it will be returned to more reasonable and rational references for decision making in overseas NG pipe-line project.

• Journal of The Korean Association For Science Education
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• v.37 no.5
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• pp.879-889
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• 2017

The purpose of this study is to develop the evaluation criteria for students' research reports on online science inquiry problems that promote thinking abilities. The steps of developing the evaluation criteria are as follows; First, based on previous study results and literature review, the evaluation categories of the science inquiry contents were determined: 1) knowledge, 2) logical and analytical thinking, 3) critical thinking, 4) science process skills, 5) problem-solving, and 6) creative thinking. Second, evaluation criteria are developed according to the following steps: 1) define each category, 2) identify sub-category, 3) develop evaluation criteria for all categories that could serve as guidelines in the development of scoring rubrics, and 4) expert validation processes were performed. Finally, the usability test for these evaluation categories and criteria were done by being applied to the development of real scoring rubrics for 24 problems included in e-learning contents. Then the users' feedbacks were filed and the implications of this study were discussed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.72-80
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• 2018

In this research, we tried to investigate the influence of concrete on cracks after applying to the actual construction site using the TPS construction method which can be easily charged by the mechanical injection method. To summarize the results, the following It is as follows. First, in the case of ultrasonic velocity, it can be seen that the ultrasonic wave passes rapidly at an average of about 36 mm / sec as compared with the syringe method when using the TPS method, and in the case of the injection depth, the syringe method In the case of TPS construction method, it showed an excellent tendency that 100% of the water retentive material was charged with all the formulations under a strong injection pressure. In the case of compressive strength, it was shown that the average was increased by 16.8% at the time of using the TPS construction method, and it was found to be structurally superior. Taken together, it is possible to confirm the behavior of the crack repairing agent by improving the quality by improving the strength and confirming the window installation by filling the injection material into the closed space at the crack site when using the TPS method compared with the syringe method. In addition, it is expected that construction time will be improved by shortening the construction period of about 5 days for the TPS construction method construction section 532 m, and usability will be expanded by the crack repair method of concrete structure.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.332-342
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• 2018

This study is aimed at suggesting information about technical choices for designing LED camping lights based on emotional lighting contents of integrated IOT and design areas which take a central role in creation and knowledge based industries and the procedure for materializing them. 'i-Light,' a portable LED camping light, is 'connected lighting' connecting men, space and emotion and a smart camping light based on IOT and emotional lighting contents. 'i-Light' has two functions. One is about lighting for adjusting color and color temperature naturally and the other is about safety for detecting harmful gases. 'i-Light' also has various emotional functions for experiencing interaction and taste of light. For the purpose, portable LED camping lights were designed, first of all, and then a highly color rendering/full-color lighting module, a smart sensor module and an IOT device platform were developed. In addition, efforts were made to establish detailed data about emotional lighting contents and to develop a Web application based on them. Finally, prototypes of portable LED camping lights were made to get a test bench and usability evaluation from related organizations. According to the results, all of 12 developed emotional lighting contents and three IOT safety sensors were suitable and prototypes were satisfactory. This paper will suggest a direction about actual technical choices for development of contents and products integrating artificial intelligence and big data and about the procedure for materializing them.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.390-397
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• 2022

Parylene-C which was mainly used for industries such as electronics, machinery and semiconductors has recently been in the spotlight in the medical field due to its properties such as corrosion resistance and biocompatibility. In this study we intend to derive a plan to improve the bonding strength of Parylene-C coating with the SUS304 base material for medical use which can be applied to various medical fields such as needles, micro needles and in vitro diagnostic device sensors. Through plasma pretreatment the bonding strength between Parylene-C and metal materials was improved. It was confirmed that the coated surface was hydrophobic by measuring the contact angle and the improvement of the surface roughness of the sample manufactured through CNC machining was confirmed by measuring the surface roughness with SEM. Through the above results, it is thought that it will be effective in increasing usability and reducing pain in patients by minimizing friction when inserting medical devices and in contact with skin. In addition it can be applied to various application fields such as human implantable stents and catheters, and is expected to improve the performance and lifespan of medical parts.