• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.865-872
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• 2009

Continuous operation of aerobic sludge digestion reactor was attempted for 279 days. Anaerobic digester sludge, the target material of the experiment, was pretreated by sodium hydroxide at $40^{\circ}C$ for 120 minutes, and the pretreated sludge was fed to 5 L CSTR (continuous stirred tank reactor). Reactor performance was affected by properties of input sludge and HRT (hydraulic retention time). 6 days of HRT showed best and stable performance, and under this condition, removal rates of $NH_3$-N, SCOD, TKN, TCOD, SS, and VSS were 97.4%, 81.7%, 68.7%, 61.4%, 50.6%, and 47.0%, respectively. 73.9% of SS in anaerobic digester sludge was reduced by pretreatment and aerobic digestion. Effluent sludge had low soluble COD of 350 mg/L. This implied the sludge was stabilized and suitable for use as liquid fertilizer. Nitrification took place when HRT was higher than 4 days. $NO_3$-N concentration was as high as 658 mg/L while $NH_3$-N was as low as 20 mg/L.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.95-103
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• 2016

The absolute value management method is widely used in the most of the earth retaining construction, which evaluates the safety by comparing measurement result and management criteria. Therefore, the management criteria is the standard to evaluate the safety of the site, and in other words, the criteria is a direct factor of the evaluation. That means that the safety of the site can not be acquired if the management criteria is not proper, even though the measurement system is perfectly set. However, many of field technicians do not have rely on the current management criteria, and they even recognize the necessity of the revision. Therefore, in this study, the necessity of the revision was studied. Also, the optimum criteria selection and the application were performed based on the test results of earth retaining deflection and probabilistic theory. The absolute value management method was used for this study. The details are tabulated.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.161.1-161
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• 2003

본 시험은 곶감건조초기의 높은 습도로 인한 불량환경을 극복하고 고품질의 우수한 곶감을 생산하기 위하여 현재 국내에서 가장 많이 재배되고 있는 상주둥시와 갑주백목 품종을 사용하여 수행하였고, 저장을 통하여 곶감의 건조시기를 달리한 다음 곶감을 제조하여 상품성을 비교하였다. 저장에 따른 품종별 과중변화는 저장 30일에 품종별로 0.32~0.38%의 무게감소를 나타내었다. 과실의 경도는 저장 30일에 두품종 공히 2.3kg/$\Phi$5mm로 나타나 저장기간이 증가할수록 감소하였지만 이러한 경도의 감소는 곶감을 제조하기 위한 박피작업에는 무리가 없었다. 저장중에 발생한 비상품과는 저장 30일에 품종별로 3.2~4.2% 발생되었고 과실의 당도는 수확시와 비교하여 약간 감소하는 경향이었으며, 과실표면의 색도 역시 적색도는 약간 증가하였으나 유의성은 없었다. 곶감 건조중 무게변화는 박피 2주경에 대부분 박피시 중량보다 30~40%감소되었고 그 후는 완만하게 감소되어 처리 6주후에는 박피중량의 30% 이내로 되었다. 품종별로는 대과종인 갑주백목의 중량감소가 다소 늦었다. 박피시기가 늦을수록 감의 건조속도도 완만하여 30일 저장한 처리구는 박피후 8~9주에 건조가 완료되었다. 곶감 제조중 품종별 경도의 변화는 건조 1주후에 품종별로 0.38~0.42kg/$\Phi$5mm로 급격히 감소하였다가 건조 후기로 갈수록 다시 증가하여 건조 6주후에는 1.52~1.85kg/$\Phi$5mm나타났다. 곶감 제조후 상품성에 있어서 곶감의 당 함량은 수확직후 제조한 곶감이 저장한 후 제조한 곶감과 비교하여 약간 높은 경향이었으나 큰 차이는 없었다. 가용성 탄닌의 함량은 곶감 제조후 품종별로 0.7~0.9mg/g으로 나타나 떫은맛이 완전히 제거되었고 저장기간별로는 차이를 보이지 않았다. 곶감의 외관상 상품성을 나타낼 수 있는 색도는 박피시기가 늦어질수록 두 품종 공히 증가되었다. 특히 갑주백목 품종의 경우 수화직후 8.4인 적색도가 저장 30일후 13.2로 증가되었고 황색도도 13.5에서 33.1로 증가되어 곶감표면의 색도가 박피시기를 연장함으로써 크게 향상된 것으로 나타났다.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.1 s.35
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• pp.57-63
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• 2006

The purpose of this study is to correct data on 3 intersection ranging from Kwangchun INT. to Nongsung INT. by the means of VTR recording and site survey and to measure the responsiveness of performance index by diversifying the platoon dispersion factor in signal progression simulation. The results are as follows : 1. The value of platoon dispersion factor was 0.28-0.33. The value in up stream is lower than that of in down stream even on the same intersection. 2. The platoon index showed big changes, though performance index didn't according to platoon dispersion factor. Therefore the value of platoon dispersion factor which is inner variable in T7F can be fixed for 0.34. 3. There was only little divergence in performance index changes according to platoon dispersion factor in designing the progression or T7F model.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.247-257
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• 2017

The purpose of this study was to measure the depression level of college students and to analyze the effects of college life stress and circadian rhythm on depression. A questionnaire survey was conducted to 720 students of college in Gwangju area from October 10, 2016 to October 31, and 687 of the collected questionnaires were analyzed. As this result, 34.5% of the students needed treatment for depression, and 71.6% of the students had mild depression. Second, depression was higher in female students, in higher grade students and students living apart from their parents. Third, evening activity type showed higher depression than morning activity type. Fourth, regression analysis revealed that depression was influenced by stress of value problem, circadian rhythm, academic stress, and getting a job stress. The results of this study suggest that students should be able to detect depression early and run a mental health program to relieve college life stress in college. However, this study is limited to some local college students and is not suitable for generalization. It is necessary to conduct research to compare university students and college students in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.6
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• pp.32-39
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• 2011

Even if the traffic light is green, if vehicles enter a jammed intersection, they are violation of the law. The police is enforcing law as a part of a nation wide campaign. Because, using the camcorder, the police can not do enforcement the offending vehicle, there are other techniques. Our research group proposed automated photographic equipment enable to enforce moving violation in intersection. Using new license plate recognition technology and backtracking technology to trace the offending vehicle, once the system detects a violator, it records 8 wide pictures and 1picture from the front vehicle, showing it enter and proceed through the intersection. Field experimental results obtained in the system, the following conclusions. The three measures of effectiveness investigated were recognition rate 83.5, mis-match recognition rate 1.5%.

• Journal of Adhesion and Interface
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• v.3 no.4
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• pp.37-43
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• 2002

A number of thin-film deposition technologies have been developed. However, even a thin film whose properties are excellent may not be used as long as the adhesion strength between the thin film and the substrate is poor. For thin films, the adhesion strength is as important as the properties. In the present article, relation between interface structure and thin film adhesion, and factors affecting thin film adhesion are reviewed. Two kinds of factors, internal factors and external factors, affect thin film adhesion. Such factors as composition, structure, and reactivity of both thin film and substrate as well as surface roughness of the substrate and residual stress of the thin film belong to internal factors. And such factors as load, temperature, humidity, and corrosive environment belong to external factors. It is also reviewed that how we can control the internal factors and the external factors to enhance or keep the adhesion strength.

• Journal of the Korean Society for Library and Information Science
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• v.36 no.4
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• pp.293-309
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• 2002

This study explores what kinds of strategies are appropriate or needed for the academic librarians to upgrade their skills in the digital age. Printed and electronic sources related to this topic are gathered and examined, and communication with some academic librarians in USA is used for this study. The skills suggested in this paper mostly come from business-oriented concepts ike Learning Organization, Knowledge Management, Team Management, Customer-Oriented Services, and Change Management. As a result of this study, it is found that these skills can be used without much difficulties in academic libraries to improve their services. However academic librarians need to keep in mind the core values of academic libraries as an academic forum and non-profit organization when they endeavor to provide better services for customers in the digital age.

• The Korean Journal of Applied Statistics
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• v.18 no.3
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• pp.583-595
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• 2005

Contingency tables are used to compare counts of n-grams to determine if the n-gram is a true collocation, meaning that the words that make up the n-gram are highly associated in the text. Some statistical methods for identifying collocation are used. They are Kulczinsky coefficient, Ochiai coefficient, Frager and McGowan coefficient, Yule coefficient, mutual information, and chi-square, and so on. But the main problem is that these measures are based ell the assumption of a nor-mal or approximately normal distribution of the variables being sampled. While this assumption is valid in most instances, it is not valid when comparing the rates of occurrence of rare events, and texts are composed mostly of rare events. In this paper we have simply reviewed some statistics about testing association of two words. Some randomization tests to evaluate the significance level in analyzing collocation in large corpora are proposed. A related graph can be used to compare different lest statistics that ran be used to analyze the same contingency table.

• Journal of the Korean GEO-environmental Society
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• v.11 no.12
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• pp.13-18
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• 2010

This study was made on the fact that the environmental impact and durability of the recently developed alkali silicasol chemical grout material. The grout material used for this study was designed to understand its environmental impact and durability through the SEM, chemical resistance test, leaching test, permeability test. In order to compare with the engineering characteristics regarding alkali silicasol grout material and sodium silicate grout material. As a result of SEM, the surface and internal tissues of alkali silicasol grout material could be identified to be denser than those of sodium silicate. As a result of leaching test the adaptability was identified as grout material as it had proved to be an ecological material owing to the total amount of the element to be leached being extremely little. As a result of permeability test it is judged that it is possible to apply the silicasol to the site in the place requiring the water cut-off as the silicasol.