• Journal of the Korean Chemical Society
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• v.46 no.3
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• pp.265-278
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• 2002

A concept test was administered to college students and teachers to identify their understanding of chemical equilibrium and equilibrium shift. The subjects were 53 freshmen in the General Chemistry class, 28 juniors in the Physical Chemistry class and 26 seniors from a university and 10 high school teachers in Seoul. Test items include the calculations of partial pressure and concentration of the gas in the mixture, the equilibrium constant cal-culation and the prediction of equilibrium shift when an inert gas is added to the gaseous reaction system, and the equilibrium concentration calculation and the prediction of equilibrium shift when water or common ion is added to the weak acid solution. The test was focused to identify whether the subjects can predict equilibrium shift using the reaction quotient change for the situations in which Le Chatelier principle is difficult to apply. The results showed that the achievements of teachers and juniors were significantly higher than those of freshmen and seniors. Many stu-dents had difficulties in predicting equilibrium shift using the reaction quotient while they could calculate partial pres-sure and concentration for the same situation. It means they are lack of conceptual understanding of chemical equilibrium shift.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.109-115
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• 2014

The purpose of this study is to estimate the sediment volume concentration of the liquified-solid mixture which is included fine sediment fractions, according to the variance of the channel slope and the water supply. The numerical model was performed by using the Finite Differential Element Method (FDM) based on the equation for the mass conservation, momentum conservation and the equation of coarse sediment an fine sediment. In comparison of varying the channel slope, the deeper the channel slope, the inflection point of the sediment concentration was occurred rapidly. In comparison of variance of the water supply, as the water supply increases fluctuation with high sediment concentration. In this situation, debris flow changes to the turbulent flow and the sediment becomes to be floated. In comparison varying the length paved saturated sediment, the longer the length, the high concentration of sediment occurred, for the safety of the slope it is needed to check the possibility of the erosion in the slope by debris flow. The results of this study will provide useful information in predicting of the disaster by the liquified-solid mixture and in prevention of the debris flow with various the slope in the mountain side.

• Journal of the Korean earth science society
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• v.34 no.6
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• pp.479-491
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• 2013

Products of the eruption of Mt. Baekdusan are identified as volcanic materials at the estuaries of the Songhuagang river to north, the Dumangang river to east and the Amnokgang river to west. More speficially, pyroclastic flows, lahars and volcanic floods can affect an area of 400km in radius, centering around Lake Cheonji caldera. However, unlike the millenium eruption, the flow situation has been changed. Because multi-purpose dams and reserviors with a combined pondage of mora than 2 billion tons of water have been built in the rivers of which sources are originated from Lake Cheonji caldera. In addition, the flow of fluids expected to take place when the volcano has erupted is thought to be affected by artificial constructions in both direct and indirect ways. This study calculates the direction of fluids flow by using numerical analyses of pyroclastic flows, lahars and volcanic floods that can occur when the volcano of Mt. Baekdusan has erupted. We also estimate the scope of damages by pyroclastic flows, lahars, volcanic flooding caused by the pondage of the dams and water storages in and around Mt. Baekdusan. Pyroclastic flows transported over the steep slopes at the early times of eruptions move over the mountain slopes, affecting airplanes, and lahars due to leaks of Lake Cheonji could reach as far as major rivers and streams near Mt. Baekdusan. Unlike historical accounts, volcanic flood is expected to be limited in its scope of influence to reservoirs bigger than Lake Cheonji in pondage.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.3
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• pp.101-124
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• 2020

Plan S is a policy that mandates research papers supported by specific funders such as the European Community be published in open access journals. The funder supports APC to researchers, providing a chance to advance the era of gold open access, and is expected to bring significant changes to the scholarly publishing ecosystem. This study explored the impact of Plan S from the perspective of each stakeholder of the scholarly publishing ecosystem, such as funders, academic societies or publishers, authors, and libraries, through a review of previous studies. In addition, the status of Korean gold open access publishing and position for each stakeholder were identified through the collected data analysis. As a result of the analysis, the share of publishing gold open access journals in Korea was 22%, which was less than 26% worldwide. Korean funding agencies were predicting and preparing for the impact of Plan S. On the other hand, Korean academic societies produce about 70% of all papers, but there are not many open access papers except medicine (51%). The response of the Korean library was not sufficient, and it contrasted with the activities of librarians in the U.S. that actively provide research support services based on the research lifecycle. It was suggested that Korean libraries should also actively try to change the role of librarians; advising researchers to plan open access publishing in grant project applications, consulting on copyrights, and so on. This study identified the background, principles, and impact of Plan S policy that would be effective in 2021 and examined the response situation in Korea. This study is valuable in that it served as the necessary basis for revitalizing the academic publishing ecosystem in Korea.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.130-139
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• 2016

A frequency of earthquake occurrence in the Republic of Korea is increasing over the past few decades. In this situation, an importance of earthquake prevention comes to the fore because the earthquake does damage to structures and causes severe damage of human life. For the earthquake prevention, a real-time vibration measurement for structures is important. As an example, the United States of America and Japan have already been monitoring real-time earthquake acceleration for the important structures and the measured acceleration data has been managed by forming database. This database could be used for revising the seismic design specifications or predicting the damage caused by earthquake. In Korea, Earthquake Recovery Plans Act and Enforcement Regulations are revised and declared lately. Ministry of Public Safety and Security is constructing a integrated management system for the measured earthquake acceleration data. The purpose of this research is to develop a real-time vibration monitoring and analysis system for structures which links to the integrated management system. The developed system contains not only a monitoring function to show real-time acceleration data but also an analysis system to perform fast fourier transform, to obtain natural frequency and earthquake magnitude, to show response spectrum and power spectrum, and to evaluate structural health. Additionally, this system is designed to be able to link to the integrated management system of Ministry of Public Safety and Security. It is concluded that the developed system can be useful to build a safety management network, minimize maintenance cost of structures, and prevention of the structural damage due to earthquake.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.1
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• pp.52-61
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• 2000

The field surveys and the seawater analyses were conducted over the southern waters of Cheju island every month from July 1997 to June 1988. The distributions of dissolved inorganic nitrogen(DIN), dissolved inorganic phosphorus(DIP), chemical oxygen demand(COD) and dissolved oxygen(DO) in the southern water area of Cheju island were simulated and reproduced by an ecosystem model. In order to estimate the environmental capacity of the southern coastal area of Cheju island, the simulations for predicting the situation of unfavorable environment in which marine water quality might not be satisfied with Korean standards were performed with an ecosystem model by controlling quantitatively the pollution loads of discharge sources including streams flowing into the sea. The more the loads of 4 major pollution sources flowing into model region increase, the more evident appear the increases of COD, DIN and DIP concentrations around the water areas adjacent to pollution sources. In case the pollution loads of all 4 discharge sources including streams become 3 times as high as the present loads, the concentration of DIN at near-shore waters appears to be increased to about 14.5mmol/m³(=0.20mg/ℓ) which is the third class criterion of Korean standards for marine water quality. In case of 10 times as high as the present loads, COD at near-shore waters appears to be increased to about 1.0mg/ℓ which is the first class criterion of Korean standards. In case of 20 times as high as the present loads, DIP at near-shore waters appears to be increased to about 0.50mmol/m³(=0.015mg/ℓ) which is the second class criterion of Korean standards.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.96-107
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• 2015

VANET technologies provide real-time traffic information for mitigating traffic jam and preventing traffic accidents, as well as in-vehicle infotainment service through Telematics/Intelligent Transportation System (ITS). Due to the rapid increasement of various requirements, the vehicle communication with a limited resource and the fixed frame architecture of the conventional techniques is limited to provide an efficient communication service. Therefore, a new flexible operation depending on the surrounding situation information is required that needs an adaptive design of the network architecture and protocol for efficiently predicting, distributing and sharing the context-aware information. In this paper, Vehicle-to-Infrastructure (V2I) based on communication between vehicle and a Road Side Units (RSU) and Vehicle-to-Vehicle (V2V) based on communication between vehicles are effectively combined in a new MAC architecture and V2I and V2V vehicles collaborate in management. As a result, many vehicles and RSU can use more efficiently the resource and send data rapidly. The simulation results show that the proposed method can achieve high resource utilization in accordance. Also we can find out the optimal transmission relay time and 2nd relay vehicle selection probability value to spread out V2V/V2I collaborative schedule message rapidly.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.871-874
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• 2010

Needs for Smart Grid development are increasing all over the world as a solution to its problem according to depletion of energy resources, climatic and environmental rapidly change and growing demand for electrical power. Especially decentralized power is attracting world's attention. In this mood a new era for a unit scale of decentralized power environment is on its way in building. However there is a problem to have to be solved in the uniformity of power quality because the amount of power generated from renewable energy resources such as wind power and solar light is very sensitive to climate fluctuation. And thus this paper tries to suggest an energy management method on basis of real time monitoring for meteorological data. In the current situation of lacking in USN-based killer application in Smart Grid field, this paper proposes the USN-based DER management system which collects the meteorological data and control power system througout utilizing wireless sensor network technique this business. This communication technique is regarded to be efficient in aspects of installation cost and tits maintenance cost. The proposed EMS model embodies the method for predicting the power generation by monitoring and analyzing the climatic data and controling the efficient power distribution between the renewable energy and the existing power. The ultimate goal of this paper is to provide the technological basis for achieving zero-energy house.

• Tunnel and Underground Space
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• v.30 no.2
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• pp.109-135
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• 2020

Globally, the deepening depth in the underground is a situation of the high interest for a purpose of the development of various facilities. The development of deep underground space should be based on the structural stability of rocks. Spalling is known to have an impact on the structural stability degradation in deep underground space. As an attempt to predict spalling, many researchers have proposed predicted conditions in accordance with stress states which occur around the tunnel, rock conditions, and types of rock. In addition, the analysis on spalling method has been verified by using computer modeling such as FLAC, EXAMINE, Insight 2D, UDEC and FRACOD, along with in-situ measurement results. In Canada URL (Underground Research Tunnel), CWFS model (Cohesion Weakening Frictional Strengthening) was used to precisely predict for the state of spalling, comparing spalling modeling. CWFS model has been identified as a reliable method for predicting such phenomena. This study aims to analyze several cases of spalling, and then make a comparison between the conditions for spalling occurrence and the predicted results of model CWFS. With this, it investigates the applicability of prediction of spalling, targeting pillar under deep depth condition.

• The Journal of Society for e-Business Studies
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• v.23 no.3
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• pp.207-224
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• 2018

In this article, an empirical study was conducted by using public dataset from Lending Club Corporation, the largest online peer-to-peer (P2P) lending in the world. We explore significant predictor variables related to P2P lending default that housing situation, length of employment, average current balance, debt-to-income ratio, loan amount, loan purpose, interest rate, public records, number of finance trades, total credit/credit limit, number of delinquent accounts, number of mortgage accounts, and number of bank card accounts are significant factors to loan funded successful on Lending Club platform. We developed online P2P lending default prediction models using discriminant analysis, logistic regression, neural networks, and decision trees (i.e., CART and C5.0) in order to predict P2P loan default. To verify the feasibility and effectiveness of P2P lending default prediction models, borrower loan data and credit data used in this study. Empirical results indicated that neural networks outperforms other classifiers such as discriminant analysis, logistic regression, CART, and C5.0. Neural networks always outperforms other classifiers in P2P loan default prediction.