• Journal of Korean Society of Water and Wastewater
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• v.22 no.6
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• pp.609-617
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• 2008

Water pipes are supposed to deliver the predetermined demand safely to a certain point in water distribution system. However, pipe burst or crack can be happened due to so many reasons such as the water hammer, natural pipe ageing, external impact force, soil condition, and various environments of pipe installation. In the present study, the reliability model which can calculate the probability of pipe breakage was developed regarding unsteady effect such as water hammer. For the reliability model, reliability function was formulated by Barlow formula. AFDA method was applied to calculate the probability of pipe breakage. It was found that the statistical distribution for internal pressure among the random variables of reliability function has a good agreement with the Gumbel distribution after unsteady analysis was performed. Using the present model, the probability of pipe breakage was quantitatively calculated according to random variables such as the pipe diameter, thickness, allowable stress, and internal pressure. Furthermore, it was found that unsteady effect significantly increases the probability of pipe breakage. If this reliability model is used for the design of water distribution system, safe and economical design can be accomplished. And it also can be effectively used for the management and maintenance of water distribution system.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.185-196
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• 2013

In Yongwon channel, its natural flow of seawater is blocked by the construction of Busan Newport including the container berth. The channel was transformed into a narrow and long one, where it is possible that ships are only allowed to pass through the north-side channel of Gyeonmado located at the point of river mouth to Songjeongcheon. In addition, Yongwon channel is approximately 100 m wide on average and 3,600 m long, which has the highest slenderness ratio (length/width=36). So it is considered that the changes in the terrain characteristics of Yongwon channel is likely to alter the circulation of sea water, thereby changing its water quality. In this study, the seasonal change and the spatial variation of the water quality in Yongwon channel was analyzed for the effect of land pollution using the measurement data. The mass balance calculation method is used to analyze the water pollution resulting from sediment pollutants. This result shows that the improvement of the water quality in Yongwon channel can be obtained from the sewer pipe modification and the environmental dredging.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.676-685
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• 2012

As impermeable layer continues to increase with the urbanization process, direct input of nonpoint source pollutants into water bodies via stormwater has caused serious effects on the aquatic ecosystem. Potential applications of rain gardens are increasing not only as best management practices (BMP) for reducing the level of nonpoint source pollutants but also as an ecological engineering alternative for low impact development (LID). In this study, remediation performance of various planting types, such as a mixed planting system with shrubs and herbaceous plants, was assessed quantitatively to effectively manage stormwater and increase landscape applicability. The mixed planting system with Rhododendron lateritium and Zoysia japonica showed the highest removal performance of $76.9{\pm}7.6%$ and $58.4{\pm}5.0%$ for total nitrogen and $89.9{\pm}7.9%$ and $82.4{\pm}5.2%$ for total phosphorus at rainfall intensities of 2.5 mm/h and 5.0 mm/h, respectively. The mixed planting system also showed the highest removal performance for heavy metals. The results suggest that a rain garden with the mixed planting system has high potential applicability as a natural reduction system for nonpoint source pollutants in order to manage stormwater with low concentrations of pollutants and will increase water recycling in urban areas.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.1
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• pp.112-123
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• 1997

This study investigated the effect of high-rise buildings on the preference for rural landscapes. The study site was a Seoul suburban, Yong-in, which showed typical scenes of rural development. Slides used in the study were taken in Young-in along the national road 45(north-south) and national road 42(east-west). Forty slides reflecting typical characters of Young-in were selected. Among them, ten slides which were selected through factor analysis based on “ruralits”score were used as original slides. They represent ten landscape types. The simulation of original slides was based on the following aspects: a observation distance. number of buildings and landscape types. The preferences for the landscapes were tested by 200 respondents on 40 slides: Distance(2) ${\times}$ Landscape type(10) = 20 slides, Number of buildings(2) ${\times}$ Landscape type(10) = 20 slides. The following results are found: 1) When high-rise buildings are introduced into rural scenes, there are some vulnerable landscape types: the landscape with high “rurality”, the landscape with background skyline and the focal landscape. 2) The observation distance affects landscape preference. The hypothesis that the nearer the distance the lower the preferences, is accepted. However, there are some exceptions in 3 landscape types. 3) The hypothesis that the more the number of buildings, the lower the preferences, is rejected. The result is quite unexpected one. When a single building is introduced in natural scene, it draws more attention as a focal point than a group of buildings, and subsequently the visual impact is stronger.

• Korean Journal of Social Welfare Studies
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• v.45 no.2
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• pp.289-325
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• 2014

In spite of theoretical logics about the necessities and effects of community networking, we have easily watched the failure of netwoking efforts and break of community networks in everyday life. Starting from these experiences, I tried to understand the process of community networking from the networkers'point of view, by the qualitative research method. Through qualitative in-depth interviews on the 6 experienced social workers in 4 communities, I analyzed their experiences of community network building, presented the results(practical guidelines), especially for the social workers expecting to be a community netwoker themselves. They consist of 10 categories and 5 themes(Being a leader/leaderships, partnership/teamwork building, understanding the impact of context, resource usage, netwoking sustaining).

• Journal of IKEEE
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• v.24 no.4
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• pp.921-930
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• 2020

The Counter-battery radar estimates the origin and impact point of the artillery by tracking the trajectory of the shell. In addition, it has the ability of identifying the type of weapon. Depending on the position between the shell and the radar, the detected signals appear differently. This has ambiguity to distinguish the type of shells. This paper compares fuzzy logic and artificial intelligence, which classifies type of shell using the parameter of signal processing step. According to the research result, artificial intelligence can improve identification rate of type of shell. The data used in the experiment was obtained from a live fire detection test.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.3
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• pp.217-227
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• 2024

This study investigated the effects of social responsibility activities on consumer attitudes, product evaluation, corporate support, and corporate trust through structural equations and path analysis. Corporate social responsibility activities were divided into five areas: consumer and environmental protection, social contribution, cultural business, and economic responsibility, and the relative impact on consumer attitudes was considered. The results and strategic implications of this study are as follows. The same results as in previous studies confirmed that the performance of corporate social responsibility activities induces positive attitudes and behaviors of consumers. It proved that the performance of corporate social responsibility activities leads consumers to form a positive attitude, which can eventually be transferred to products and corporate images by a halo effect, leading to product evaluation, corporate support and trust. In addition, the composition dimension and measurement items of corporate social responsibility activities were re-verified, and from a consumer point of view, it was confirmed that social responsibility activities include not only economic activities, but also activities that contribute positively, such as social contribution, support for local and cultural projects, and actions that do not harm society as a whole, such as protecting consumer rights and protecting the environment.

• Journal of Ocean Engineering and Technology
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• v.38 no.4
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• pp.174-186
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• 2024

In coastal video monitoring, the direct linear transform (DLT) method with ground control points (GCPs) is commonly used for geo-rectification. However, current practices often overlook the impact of GCP quantity, arrangement, and the geographical characteristics of beaches. To address this, we designed scenarios at Chuam Beach to evaluate how factors such as the distance from the camera to GCPs, the number of GCPs, and the height of each point affect the DLT method. Accuracy was assessed by calculating the root mean square error of the distance errors between the actual GCP coordinates and the image coordinates for each setting. This analysis aims to propose an optimal GCP placement method. Our results show that placing GCPs within 200 m of the camera ensures high accuracy with few points, whereas positioning them at strategic heights enhances shoreline extraction. However, since only fixed cameras were used in this study, factors like varying heights, orientations, and resolutions could not be considered. Based on data from a single location, we propose an optimal method for GCP placement that takes into account distance, number, and height using the DLT method.

• 한국경영정보학회:학술대회논문집
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• 2007.06a
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• pp.184-189
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• 2007

Concerns about food safety continue to rise and under this situation, governments of some countries have reinforced their regulations more strictly for food safety. In order to prevent food safety incidents or, at least to minimize the impact, the preparedness is very important. As a consequence of this, traceability system has become an essential tool for food safety. Recently, it requires more prevention-based food safety control system. One of the most generally used systems for food safety control is Hazard Analysis and Critical Control Point (HACCP). Both traceability and HACCP systems can be integrated through Electronic Product Code (EPC) Sensor Network technologies which have four value propositions. In this paper, we will introduce the concept of product and process traceability system (P2TS) through the integration of three systems to improve food safety management. The final aim is to find out the added values of the P2TS.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.11
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• pp.2992-3007
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• 2012

Recently there has been an increasing interest in exploring the radio irregularity research problem in Wireless Sensor Networks (WSNs). Measurements on real test-beds provide insights and fundamental information for a radio irregularity model. In our previous work "LMAT", we solved the path planning problem of the mobile anchor node without taking into account the radio irregularity model. This paper further studies how the localization performance is affected by radio irregularity. There is high probability that unknown nodes cannot receive sufficient location messages under the radio irregularity model. Therefore, we dynamically adjust the anchor node's radio range to guarantee that all the unknown nodes can receive sufficient localization information. In order to improve localization accuracy, we propose a new 2-hop localization scheme. Furthermore, we point out the relationship between degree of irregularity (DOI) and communication distance, and the impact of radio irregularity on message receiving probability. Finally, simulations show that, compared with 1-hop localization scheme, the 2-hop localization scheme with the radio irregularity model reduces the average localization error by about 20.51%.