• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2B
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• pp.211-217
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• 2010

This paper presents numerical investigations of the physical habitat changes induced by the hydropeaking in the downstream river of dam. For the two-dimensional ecohydraulic simulations, River2D model is used. Pirami (Zacco platypus) is selected as the target fish for investigating the impact of the hydropeaking. For validation of the model, the water surface elevations are simulated with two different water discharges. The computed results are compared with field data in the literature, and the result shows that the model successfully simulates the water flows. The weight usable area (WUA) of Pirami with the life cycle and the composite suitability index with different water discharges are computed and discussed. The results show that habitat for Pirami appears to be best in the bend region downstream of the dam. The discharge of the maximum WUA for adult Pirami is computed to be about 9 $m^3/s$. Also, the WUA computed in a condition of hydropeaking during seven days are presented. The averaged discharge of the hydropeaking appears to be about 20% larger than the drought flow, but the WUA by the hydropeaking is computed to be 60-100% smaller. This result shows that the hydropeaking reduces quantity of habitat available to fish.

• Journal of Distribution Science
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• v.13 no.9
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• pp.95-101
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• 2015

Purpose - This study provides evidence of the impact of the mandatory adoption of Korean equivalents to International Financial Reporting Standards (K-IFRS) on accounting quality. K-IFRS uses fair value as a basis of measurement and is characterized by principle-based standards. These characteristics can lead to a decrease in conservatism. Therefore, this study aims to examine whether or not there is a change in the level of conservatism before and after the enforcement of K-IFRS (2007~2014). By comparing 2007 through 2008 and 2013 through 2014 (excluding 2009 to 2012), we test "the temporary adjustment phenomenon" and document an overall decline in the degree of conservatism after the adoption of K-IFRS. Research design, data, and methodology - Our sample is comprised of data of all listed Korea Composite Stock Price Index (KOSPI) manufacturing distribution companies in Korea from 2007 to 2014, which yields the pooled sample of 4,412 (panel A) and 1,915 (panel B) firm-year observations for hypotheses 1 and 2. In line with recent literature, we adopt the Givoly and Hayn (2000) model, which recomputes the non-operating accruals, excluding two components that are most likely to capture the effect of restructuring activities: special items and gains or losses from discontinued operations. In addition, we also use these variables: SIZE, LEV, INV_CYCLE, ROA, OWN, and FOR. Results - Our sample period spans 2007 to 2014. This offers evidence on the effect of the mandatory adoption of IFRS on conservatism. Our findings can be summarized as follows. First, in panel A, for mandatory K-IFRS adoption (2011), we do not find any significant evidence of conservatism. We can guess that the "temporary adjustment phenomenon" is the reason that we do not find significant evidence of conservatism. Second, we investigate panel B from 2009 to 2012. We document an overall decline in the degree of conservatism after the adoption of K-IFRS. We can assume that these results are due to "the temporary adjustment phenomenon." Conclusions - This study finds that conservatism significantly decreased after IFRS adoption. In particular, this study makes the initial effort to elucidate "the temporary adjustment phenomenon" to analyze the effect of K-IFRS on conservative accounting. We argue that K-IFRS are conceptually conservative but that inappropriate application of the conservatism principles is likely to prevent financial reporting from reaching the level of conservatism targeted by the IASB. Overall, this paper contributes to the literature on IFRS and can be useful to capital market supervisors who are monitoring the trends of the firms implementing K-IFRS. Additionally, our results inform stakeholders of the potentially negative effect of the greater flexibility permitted by IFRS and/or lack of appropriate enforcement on key dimensions of accounting quality. This has important implications for Korean regulators and standard setters as they review the cost and benefits of IFRS. Our study also sheds light on the importance of the institutional environment in achieving the targeted objectives for improving financial reporting quality.

• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.305-317
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• 2023

This study suggested a citizen science based model to enhance the efficacy of the managing invasive alien plants and examined whose applicability in 3 Wetland Protected Areas (Jangrok of Gwangju metropolitan city, Madongho of Goseong in South Gyeongsang Province, and Ungok of Gochang in North Jeolla Province). The process consists of (a) collecting citizen scientist including local residents of 3 protected areas and piling up information on the 4 species of invasive alien plants (Sicyos angulatus L., Solanum carolinense L., Ambrosia artemisiifolia L. and Solidago altissima L) in a information platform Ecological Information Bank (EcoBank) from September 18th to October 31th, (b) constructing distribution map containing the location and density (3 phases: individual-population-community) of target plants, (c) providing distribution map to Environment Agency and local government who is principal agent of managing invasive alien plants in 3 protected areas, and from whom (d) surveying applications of the distribution map and opinion for future supplement. As a result, citizen science based monitoring should be continued to complement the nationwide information for the field management of invasive alien plants with the expansion of target species (total 17 plants species that Ministry of Environment in South Korea designated) and period of monitoring in a year to increase the usability of surveyed information from citizen science. In the long run, effectiveness of the management of invasive alien species applied by citizen science should be reviewed including efficacy of field management process from citizen's participating in elimination project of invasive alien plants and time series distribution followed by the management of the species.

• Journal of Forest and Environmental Science
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• v.28 no.3
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• pp.158-169
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• 2012

Sabah has experienced a rapid decline in the extent of forest cover. The precise impact of habitat loss on the conservation status of the plants of Sabah is uncertain. In this study we use the niche modelling algorithm MAXENT to construct preliminary, revised and final ecological niche models for Dipterocarpus lamellatus and Dipterocarpus ochraceus and combined these models with data on current land-use to derive conservation assessments for each species. Preliminary models were based on herbarium data alone. Ground surveys were conducted to evaluate the performance of these preliminary models, and a revised niche model was generated from the combined herbarium and ground survey data. The final model was obtained by constraining the predictions of the revised models by filters. The range overlap between the preliminary and revised models was 0.47 for D. lamellatus and 0.39 for D. ochraceus, suggesting poor agreement between them. There was substantial variation in estimates of habitat loss for D. ochraceus, among the preliminary, revised and constrained models, and this has the potential to lead to incorrect threat assessments. From these estimates of habitat loss, the historic distribution and estimates of population size we determine that both species should be classified as Critically Endangered under IUCN Red List guidelines. Our results suggest that ground-truthing of ecological niche models is essential, especially if the models are being used for conservation decision making.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.155-165
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• 2014

In this study, using a complex of physical, chemical, and biological evaluation factors, the ecological vulnerability to climate change were evaluated at each river in the Nakdong river basin. First, runoff, sediment rate, and low flow discharge changes according to AIB climate change scenario using the SWAT model were simulated. Also, for the assessment of chemical and biological factors, 48 points that water quality monitoring sites and ecological health measurement points are matched with each other was selected. The water quality data of BOD and T-P and the biological data of IBI and KSI in each point were reflected in the assessment. Also, the future rise in water temperature of the rivers in Nakdong river basin was predicted, and the impact of water temperature rise on the fish habitat was evaluated. The top 10 most vulnerable points was presented through a summary of each evaluation factor. This study has a contribution to river restoration or management plan according to the characteristics of each river.

• Journal of KIISE:Information Networking
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• v.33 no.2
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• pp.183-192
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• 2006

This paper analyzes the price-selection problem under priority-based scheduling for QoS (Quality of Service) network services, i.e., how to determine the price associated with each service level. In particular, we focus on the problems with the pricing mechanism based on equilibrium analysis. We claim that the assumptions needed to produce equilibrium nay not hold in some important environments. Specifically, (a) the individual user's impact on the system is not infinitesimal and (b) users do not always have up-to-date global system-status knowledge crucial for optimal user decisions required for equilibrium. These may make the equilibrium models inaccurate in realistic environments. We examine the accuracy of some existing equilibrium methods by using a dynamic model that we have developed for system behavior analysis. The analysis indicates that equilibrium methods fail to model accurately the system behavior in some realistic environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10B
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• pp.831-840
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• 2004

Providing quality of service (QoS) guarantees over wireless link requires thorough understanding and quantification of the interactions among the traffic source, the wireless channel, and the underlying error control mechanisms. In this paper, we account for such interactions in a network-layer model that we use to investigate the delay performance of a wireless channel. We consider a single ON/OFF traffic stream transported over a wireless link. The capacity of this link fluctuates according to a fluid version of Gilbert-Elliot's model. We derive the packet delay distribution via two different approaches: uniformization and Laplace transform. Numerical aspects of both approaches are compared. The delay distribution is further used to quantify the wireless effective bandwidth under a given delay guarantee. Numerical results and simulations are used to verify the adequacy of our analysis and to study the impact of error control and bandwidth allocation on the packet delay performance. Wireless networks, QoS, delay distribution, fluid analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.3
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• pp.297-304
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• 2016

A numerical simulation has been performed for the penetration of a long-rod penetrator into a metal block (ceramic-tile-inserted 4340-steel plate). The impact velocity is 1.5km/s at a normal incidence angle. The first two validations are conducted for a semi-infinite block measuring the depth of penetration (DOP). The material model of ceramic is the JH-2 (Johnson-Holmquist) model. The predicted DOP values are in close agreement with the experimental data. Then, the primary simulation is performed by varying the position of the confined ceramic tile for three types of thickness of ceramic tile. The residual velocity, residual mass and residual kinetic energy of the long-rod are obtained from the simulation. Based on these predicted values, the trend of the ballistic performance of the protective structure is estimated. In addition, the mass efficiency is calculated in order to determine the performance of the ceramic-tile-inserted metal block. Finally, the optimum protective structure is identified.

• 한국정보컨버전스학회:학술대회논문집
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• 2008.06a
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• pp.135-140
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• 2008

Recently in the Mongolian wireless marketplace, many E-commerce companies have been making considerable investments in the technological development of M-commerce, taking competitive advantage of new business possibilities offered by Internet-based wireless technologies. In the Mongolian wireless marketplace, this new mobile environment opens the door for new and exciting market opportunities in mobile services and applications. In the near future, these companies will be looking toward M-commerce services as a supplemental source of revenue in the mobile marketplace. This paper examines the roles of M-commerce in the consumers' in order to promote the consumers' loyalty in the booming M-commerce. This paper contains theory that focuses on the basic concepts of the M-commerce environment, its wireless network technologies, and its applications infrastructure. Upon searching for references to assist us in establishing a market hypothesis, we discovered that few comprehensive studies on consumer perspective and behavior related to M-commerce services actually exist in the literature. In the area of M-commerce, many companies neglect the consumer perspective, concentrating only on technological factors only when formulating their market strategies. And, due to technological blindness, many companies were not able to succeed in end-user E-commerce services. Given that fact, this paper formulates a consumer-centric research model. In order to prove the research model, we chose the survey method which allows for the collection of large amounts of data from a sizeable population in a highly economical way. Through the survey, this paper defines consumer's attitudes towards M-commerce services by identifying potential Business-to-Commerce(B2C) applications and its primary target groups in terms of gender and age, and by investigating whether consumers recognize the value proposition of M-commerce applications and services. As shown in the data analysis and results, this research concludes that M-commerce development in Mongolia is still at its infancy, and that the implementation of M-commerce depends not only on technological progress, but also on consumer attitudes and their willingness to adopt M-commerce services. As well, other complex cross-cultural factors-socially, economically, culturally, et cetera-enter strongly into the equation.

• Information Systems Review
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• v.13 no.2
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• pp.17-41
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• 2011

A review of the related literature indicates that consumers' risk perceptions are largely affected by product involvement. This study investigates the impact of product involvement on required trust level and the online merchant choice. We developed a conceptual model that depicts the nomological relationships among product involvement, required trust level, and the online merchant choice, and formulated three hypotheses based on the conceptual model. An empirical study designed to accomplish the research objectives has been conducted using a questionnaire survey with 230 students in a university in Korea. The findings indicated that high-involvement products have higher trust level as required by consumers than low-involvement products, that consumers buying high-involvement products prefer digital storefronts, and that consumers buying low-involvement products prefer B2C e-marketplaces. The paper offers implications for academics as well as practitioners, based on the research results.