• Journal of Environmental Health Sciences
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• v.46 no.2
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• pp.150-158
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• 2020

Objective: This study is designed to measure the concentration of DBPs (disinfection by-products) in pool water and in air and to estimate the carcinogenic potential through the evaluation of inhalation exposure. Methods: The subjects were six indoor swimming pools with many users in Gwangju. Samples of pool water and indoor air were taken every one month from August 2018 to August 2019 and analyzed for eight swimming pool standards. Three-liter air samples were collected and the VOCs were analyzed using GC/MS directly connected to thermal desorption. Results: pH was 6.8-7.5 and the concentration of free residual chlorine in pool water was 0.40-0.96 ?/ℓ. Physicochemical test items such as KMnO₄ consumption and heavy metal items such as Aluminum met existing pool hygiene standards. No VOC materials were detected except for the DBPs. The concentration of THMs in the pool water was 11.05-41.77 ㎍/L and the THMs mainly consist of Chloroform (63-97%) and BDCM (3-31%). The concentration of indoor air THMs is 13.24-32.48 ㎍/㎥ and consists of Chloroform. The results of carcinogenic assessment of chloroform in the indoor swimming pool via inhalation exposure were 2.0 to 6.4 times higher than the 'acceptable risk level' suggested by the US EPA. Conclusions: The concentration of THMs in the pool water is 11.05-41.77 ㎍/L, most of which is chloroform. In addition, the concentration of indoor air THMs is 13.24-32.48 ㎍/㎥. The result of carcinogenic assessment of chloroform was 2.0 to 6.4 times higher than the 'acceptable risk level' suggested by the US EPA.

• Journal of Environmental Impact Assessment
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• v.27 no.4
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• pp.378-393
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• 2018

As atmospheric fine dust problems in Korea become more serious, there are growing needs to find the concentration of fine particles in indoor and outdoor areas and there are increasing demands for sensor-based portable monitoring devices capable of measuring fine dust concentrations instantly. The low-cost portable monitoring devices have been widely manufactured and used without the prescribed certification standards which would cause unnecessary confusion to the concerned public. To evaluate the reliability those devices and to improve their usability, following studies were conducted in this work; 1) The comparisons between sensor-based devices and comparison with more accurate devices were performed. 2) Several experiments were conducted to understand usefulness of the portable monitoring devices. As results, the absolute concentration levels need to be adjusted due to insensitivity of the tiny light scattering sensors in the portable devices, but their linearity and reproducibility seem to be acceptable. By using those monitoring devices, users are expected to have benefits of recognizing the changes of concentration more quickly and could help preventing themselves from the adverse health impacts.

• Journal of the Korean Institute of Gas
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• v.16 no.1
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• pp.39-45
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• 2012

While the natural gas supply industry has continuously been growing, its potential hazard has also risen since the natural gas facilities essentially require installations that carry highly flammable and pressurized gas close to the populated areas, posing a serious consequence of significant property damage as well as human casualties in the event of accident. Therefore Quantitative Risk Assessment (QAR) has been recognized as a appropriate method to reduce the risk as far as possible, considering the reality of unachievable zero-risk. However, it is hard to perform effective QRA on hundreds of gas facilities because of insufficient number of expert and long-term analysis. In this paper, we suggest a conceptual QRA system framework to support more efficient risk analysis in gas supply facilities. In this system, the experts make questionnaires and internal calculation formula needed in accident frequency/consequence analysis of the facility through pre-analysis on the point of analysis, called incident point, and general users locate the point on the map and input the value required by the questionnaire to obtain the risk. Ultimately, this is suggested based on the idea that the specialization is available in QRA analysis process and the validity of the system is verified through actual system construction and application.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.2
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• pp.117-126
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• 2007

This study investigated the effect of the price and brand name on the consumer's evaluation of cosmetics. 363 women from 20's to 50's living in Seoul and the metropolitan area were asked to use and describe the given samples of cosmetic products for one week with different information of price and brand name. The results of this study are as follows: First, the assessment of the facial toner, moisturizer and cream does not show a significant statistical difference between the group of 'renowned' and 'renownless'. Second, the assessment of the facial toner, moisturizer, and cream shows a significant statistical difference between the user groups which received the prior information whether the cosmetics are 'high price' or 'low price'. Third, the assessment of the users' satisfaction of the 3 kinds of cosmetic products mentioned above is influenced by 'renown' an 'price'. Finally, the interaction of the factor 'renown' and 'price' influences on the cosmetics' effectiveness significantly. From this study, it was discovered that the evaluation and the degree of satisfaction on cosmetics were influenced by the price and brand names. This will improve the understanding of consumers' behavior and personal decision-making, which in be the key of marketing strategy.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.4
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• pp.155-165
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• 2024

Software as a Service (SaaS) has become one of the fastest-growing software business models in recent years. Even during the economic downturn following the pandemic, the SaaS business has emerged as a crucial model for IT companies. The revenue structure of SaaS, which is based on the subscription economy model, ensures that users pay only for the services used. In other words, SaaS operates on a subscription-based billing model, thus providing subscribers access to software uploaded to cloud computers via the Internet. This study aimed to explore the manner by which software-solution firms have to counteract the decline in profit and loss sales caused by changing their business-model orientation from on-premise deployment software to subscription-based software. Additionally it analyzes a method for selecting a subscription-based pricing model and rapidly recovering the investment costs via quantitative business-viability assessment. By calculating subscription fees via a more quantitative business-viability evaluation instead of focusing on conventional business-planning methods that rely on qualitative methods, companies are expected to be equipped in providing services to customers at reasonable costs. This strategy will facilitate them in leading emerging growth sectors.

• Communications of Mathematical Education
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• v.37 no.2
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• pp.233-256
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• 2023

This study conducted foundational research to derive ways to use ChatGPT in mathematics education by analyzing ChatGPT's responses to questions from the National Assessment of Educational Achievement (NAEA) and the College Scholastic Ability Test (CSAT). ChatGPT, a generative artificial intelligence model, has gained attention in various fields, and there is a growing demand for its use in education as the number of users rapidly increases. To the best of our knowledge, there are very few reported cases of educational studies utilizing ChatGPT. In this study, we analyzed ChatGPT 3.5 responses to questions from the three-year National Assessment of Educational Achievement and the College Scholastic Ability Test, categorizing them based on the percentage of correct answers, the accuracy of the solution process, and types of errors. The correct answer rates for ChatGPT in the National Assessment of Educational Achievement and the College Scholastic Ability Test questions were 37.1% and 15.97%, respectively. The accuracy of ChatGPT's solution process was calculated as 3.44 for the National Assessment of Educational Achievement and 2.49 for the College Scholastic Ability Test. Errors in solving math problems with ChatGPT were classified into procedural and functional errors. Procedural errors referred to mistakes in connecting expressions to the next step or in calculations, while functional errors were related to how ChatGPT recognized, judged, and outputted text. This analysis suggests that relying solely on the percentage of correct answers should not be the criterion for assessing ChatGPT's mathematical performance, but rather a combination of the accuracy of the solution process and types of errors should be considered.

• Asia pacific journal of information systems
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• v.22 no.4
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• pp.7-29
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• 2012

Smartphone and its applications (i.e. apps) are increasingly penetrating consumer markets. According to a recent report from Korea Communications Commission, nearly 50% of mobile subscribers in South Korea are smartphone users that accounts for over 25 million people. In particular, the importance of smartphone has risen as a geospatially-aware device that provides various location-based services (LBS) equipped with GPS capability. The popular LBS include map and navigation, traffic and transportation updates, shopping and coupon services, and location-sensitive social network services. Overall, the emerging location-based smartphone apps (LBA) offer significant value by providing greater connectivity, personalization, and information and entertainment in a location-specific context. Conversely, the rapid growth of LBA and their benefits have been accompanied by concerns over the collection and dissemination of individual users' personal information through ongoing tracking of their location, identity, preferences, and social behaviors. The majority of LBA users tend to agree and consent to the LBA provider's terms and privacy policy on use of location data to get the immediate services. This tendency further increases the potential risks of unprotected exposure of personal information and serious invasion and breaches of individual privacy. To address the complex issues surrounding LBA particularly from the user's behavioral perspective, this study applied the privacy calculus model (PCM) to explore the factors that influence the adoption of LBA. According to PCM, consumers are engaged in a dynamic adjustment process in which privacy risks are weighted against benefits of information disclosure. Consistent with the principal notion of PCM, we investigated how individual users make a risk-benefit assessment under which personalized service and locatability act as benefit-side factors and information privacy risks act as a risk-side factor accompanying LBA adoption. In addition, we consider the moderating role of trust on the service providers in the prohibiting effects of privacy risks on user intention to adopt LBA. Further we include perceived ease of use and usefulness as additional constructs to examine whether the technology acceptance model (TAM) can be applied in the context of LBA adoption. The research model with ten (10) hypotheses was tested using data gathered from 98 respondents through a quasi-experimental survey method. During the survey, each participant was asked to navigate the website where the experimental simulation of a LBA allows the participant to purchase time-and-location sensitive discounted tickets for nearby stores. Structural equations modeling using partial least square validated the instrument and the proposed model. The results showed that six (6) out of ten (10) hypotheses were supported. On the subject of the core PCM, H2 (locatability ${\rightarrow}$ intention to use LBA) and H3 (privacy risks ${\rightarrow}$ intention to use LBA) were supported, while H1 (personalization ${\rightarrow}$ intention to use LBA) was not supported. Further, we could not any interaction effects (personalization X privacy risks, H4 & locatability X privacy risks, H5) on the intention to use LBA. In terms of privacy risks and trust, as mentioned above we found the significant negative influence from privacy risks on intention to use (H3), but positive influence from trust, which supported H6 (trust ${\rightarrow}$ intention to use LBA). The moderating effect of trust on the negative relationship between privacy risks and intention to use LBA was tested and confirmed by supporting H7 (privacy risks X trust ${\rightarrow}$ intention to use LBA). The two hypotheses regarding to the TAM, including H8 (perceived ease of use ${\rightarrow}$ perceived usefulness) and H9 (perceived ease of use ${\rightarrow}$ intention to use LBA) were supported; however, H10 (perceived effectiveness ${\rightarrow}$ intention to use LBA) was not supported. Results of this study offer the following key findings and implications. First the application of PCM was found to be a good analysis framework in the context of LBA adoption. Many of the hypotheses in the model were confirmed and the high value of $R^2$ (i.,e., 51%) indicated a good fit of the model. In particular, locatability and privacy risks are found to be the appropriate PCM-based antecedent variables. Second, the existence of moderating effect of trust on service provider suggests that the same marginal change in the level of privacy risks may differentially influence the intention to use LBA. That is, while the privacy risks increasingly become important social issues and will negatively influence the intention to use LBA, it is critical for LBA providers to build consumer trust and confidence to successfully mitigate this negative impact. Lastly, we could not find sufficient evidence that the intention to use LBA is influenced by perceived usefulness, which has been very well supported in most previous TAM research. This may suggest that more future research should examine the validity of applying TAM and further extend or modify it in the context of LBA or other similar smartphone apps.

• Journal of the Korean Geographical Society
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• v.35 no.1
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• pp.3-15
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• 2000

산업화와 더불어 심각해지고 있는 수질오염 문제를 해결하기 위해서는 여러 가지 수질관리 방안이 요구된다. 수질오염이 과거에는 국지적이었으나 점차 광범한 지역으로 확장됨에 다라 지속적인 수질 모니터링에 어려움이 따른다. 본 연구에서는 위성영상을 사용한 원격탐사 기법으로 수역의 수질환경 인자를 추출하고자 한다. 사용된 영상은 Landasat TM이며, 연구지역은 한강하류 지역이다. 수질분석 인자는 클로로필-a, 부유물질, 투명도 등을 선정하였으며, 수면분광반사율의 특징 및 수질인자별 처리기법을 개발하는데 목적을 두었다. 분광특성 분석결과를 요약하면, 첫 번째 스펙트럼 반사율 분석결과 클로로필-a의 농도는 0.4~0.5$\mu\textrm{m}$ 파장대역에서 낮은 반사치 경향을 보이며, 녹색파장대인 0.57$\mu\textrm{m}$ 부근에서 반사율이 높아진다. 두 번째 부유물질의 반사도는 농도가 증가할수록 0.8$\mu\textrm{m}$ 부근에서 상대적으로 낮은 반사율이 나타난다. 마지막으로 투명도가 낮은 수면은 0.55$\mu\textrm{m}$에서 높은 반사율 경향을 보인다. Landsat TM영상을 이용하여 주성분분석 및 비연산처리를 실시하여 수질분석을 시도한 결과를 보면 클로로필-a와 투명도는 제1주성분 영상 및 제2주성분 영상에서 현장 실측자료와 유사한 결과를 얻을 수 있었으며, 부유물질은 밴드 2와 밴드 4의 비연산처리를 통하여 분포도를 작성할 수 있었다. 이상의 결과들은 계절적 및 시간적 변화에 따라 파장대역이 달라질 수 있다. 그러므로 위성자료를 이용하여 보다 정확한 수질환경 인자를 추출하기 위해서는 현장실측 및 수역의 분광반사 특성을 지속적으로 조사하여야 한다.때문으로 경주 산사태와 포함-구릉포간 국도면의 산사태가 이 종류의 산사태에 속한다.열 인식의 신뢰도를 향상시킬수 있는 방법을 제안하였다.작성하여 최신 의료영상 처리 기법을 쉽게 임상에 적용하고 실험할 수 있는 장점이 있다. 지대에서 가능하였고, 파종기는 중생종보다 이르게 나타났다. 등숙만한출수기 기준의 안전작기는 조생종과 중생종은 태백고냉지대와 태백준고냉지대, 소백산간지대 일부지역을 제외한 다른 지역에서 설정되었고, 중만생종은 태백고냉지대, 태백준고냉지대, 동해안북부지대, 소백산간지대, 노령소백산간지대의 일부 지역은 벼 담수직파가 불가능하게 판단되었다. information on the regular basis of time and provide it when the users query over the Web-database gateway. The other approach is a shopping agent mechanism, which stores information on "how to shop" and the shopping agent collects the information of product items just after users query about the product and provide the information in real time or notify them by alerting service. Thirty nine shopping information services are compared and classified in this paper and they are extracted from "Naver" and "Yahoo! Korea". The final result shows that most services are just a

• Journal of Internet Computing and Services
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• v.18 no.3
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• pp.37-48
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• 2017

Touch interface has been introduced as one of the most common input devices that are widely used in the Smart Device. Recently Force-Touch interface, a new approach of input method, having the power recognition mechanism, has been appeared in Smart industries. Force-Touching determining multiple things (the geographical and pressure values of touching point) in one touching act allows users to provide more than one input methods in a limited environments. Force-Touching Device is required different user communicational interaction than other common Smart devices because it is possible to recognize various inputs in the one act. It means that Force-Touching is only able to understand and to use the pressure sensitive values, not other Smart input methods. So, we built Force-Touch-Cover that makes typical Smart-Device to have Force-Touching interfaces. We analysis the accuracy of the Force-Touching-Cover's sensor and also assessment the changes in pressure values depending on the pressure position. Via this Paper, We propose the implement of user-oriented Force-Touching interface that is based on users' feedback as our conclusion.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.4
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• pp.36-47
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• 2008

The purpose of this study is to classify and assess the characteristics of urban Korean parks by on-site park users' reactions, such as satisfaction, preference and cognitive image of the park and park facilities. The park facilities are classified into five types of satisfaction: management status, activity facilities, convenient facilities, circulation and density, and landscape facilities. The park users are satisfied with conversation, rest and relaxation in the parks, but not satisfied with studying and nature experience. The behaviors in the park are classified as park activities, emotional and experiential activities, and nature activities. The results indicate that the images of the parks are stable, comfortable and natural. There are three factors to classifying the park images: nature-harmony, openness, uniqueness. Preferences for each parks are generally good. According to the criteria such as satisfaction of park facility, behavioral satisfaction, images and preference for each park, the 12 parks are divided into 5 different types: multi-purpose park, well-balanced park with natural elements, urban open space, park to be improved, and ecological park. The characteristics of each park was analyzed and categorized. This study dealt with only the parks in Seoul and its environs, and the survey was only done during the summer season. Therefore, further research is necessary to enlarge and generalize the results of this study, considering seasonal and regional variations.