• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.381-390
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• 2023

In this study, the mechanical performance of concrete exposed to chloride ion penetration was investigated. And a compressive stress-strain model was presented. CaCl₂ solution was added when mixing concrete to simulate long-term chloride ion penetration, and the concentration of chlorine ions was set to 0, 1, 2, and 4 % based on the weight of the binder. To investigate the compressive stress-strain curve after the peak stress of concrete, the compressive strength was measured by displacement control. When the chlorine ion concentration was 1 %, peak stress increased, but when the chlorine ion concentration was 2 % or more, peak stress decreased. In the case of peak strain, no trend according to chloride ion concentration was observed at 7 days. At 28 days, peak strain decreased as the chloride ion concentration increased. A compressive stress-strain curve model based on the Popovics model was presented using changes in peak stress and peak strain at 28 days. Microstructure analyses were performed to investigate the cause of the decrease in mechanical performance as the concentration of chlorine ions increased. It was confirmed that as the concentration of chlorine ion increased, Friedel's salt increased and portlandite decreased.

• Journal of the Korea Concrete Institute
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• v.27 no.2
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• pp.185-193
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• 2015

Ultra high performance concrete (UHPC) has been developed to overcome the low tensile strengths and brittleness of conventional concrete. Considering that UHPC, owing to its composition and the use of steel fibers, develops a compressive strength of 180 MPa as well as high stiffness, the top flange of the steel girder may be superfluous in the composite beam combining a slab made of UHPC and the steel girder. In such composite beam, the steel girder takes the form of an inverted-T shaped structure without top flange in which the studs needed for the composition of the steel girder with the UHPC slab are disposed in the web of the steel girder. This study investigates experimentally and analytically the flexural behavior of this new type of composite beam to propose details like stud spacing and slab thickness for further design recommendations. To that goal, eight composite beams with varying stud spacing and slab thickness were fabricated and tested. The test results indicated that stud spacing running from 100 mm to 2 to 3 times the slab thickness can be recommended. In view of the relative characteristic slip limit of Eurocode-4, the results showed that the composite beam developed ductile behavior. Moreover, except for the members with thin slab and large stud spacing, most of the specimens exhibited results different to those predicted by AASHTO LRFD and Eurocode-4 because of the high performance developed by UHPC.

• Journal of the Korean Institute of Gas
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• v.22 no.2
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• pp.34-45
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• 2018

The cleat system in coalbed methane (CBM) reservoirs is generally occupied by water which liberated during the coalification process, and behavior of water have influence on CBM production performance. Therefore, it is essential to investigate the effect of the water saturation to operate the degasification process and predict the CBM production performance properly. In this study, type curve analyses were performed on CBM reservoirs under various water saturation to improve the prediction of production performance. A CBM reservoir models with fully-, modestly-, and undersaturated reservoir were built to get production data using GEM by CMG Ltd., and the data were matched with Fetkovich, Palacio-Blasingame(P-B), and Agarwal-Gardner (A-G) type curve. The results showed that undersaturated reservoir was successfully matched by A-G type curve, while the Fetkovich type curve was inappropriate for matching in the late time. The modestly saturated model could be almost corresponded with all the type curve methods at late production period. For the fully saturated model, after peak production had been reached, both P-B and A-G methods showed a proper match to the reservoir production data without long-term production period. Based on the results, merit and demerit of each type curve under specific water saturation were analyzed and listed. Therefore, it is believed that the production data analysis with proper type curve model considering water saturation can be performed to predict accurate production performance.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.8 no.1
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• pp.70-82
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• 1997

Objective：This study was performed to identify and understand the characteristics of adolescents who had a history of police arrest and/or were adjudicated unruly/delinquent by the juvenile court. Method：The study employed a retrospective reivew of coumputer-recorded data set on 210 consecutive admissions to an adolescent psychiatric inpatient unit. Three groups(No Police Contact, N=115；Police Contact Only, N=60；Adjudicated, N=35) were compared on the areas of a) cognitive and educational performance b) emotion：anxiety, depression, suicidality c) personality d) family and life experiences. Standardized assessments were administered to all subjects using WISC-Ⅲ, Kaufman Test of Educational Achievement, Millon Adolescent Personality Inventory, Reynolds Adolescent Depression Scale, Revised-Chilren’s Manifest Anxiety Scale, Suicide Ideation Questionnarie, Suicide Behavior Interive, Life Events Checklist, and Family Environmental Scale. A subgroup of the subjects, 60 cases also received a standardized interview by Child Assessment Schedule. Results：The characteristic findings of the delinquent group(the police contact only and adjudicated subjects combined) included (1) a high rate of adoption, sexual promiscuity, out of home placement, and repeated psychiatric hospitalization, (2) low verbal IQ scores and educational achievements, (3) high impulsivity, low social conformity, and high forcefulness in personality inventory, (4) low activityrecreation orientation and low moral religious emphasis in family environment, (5)a high frequency of adverse life experiences, (6) among 3 groups, the Police Contact Only group showed the lowest depression, anxiety and suicidal ideation scores, (7) a high diagnostic frequency of conduct disorder, ODD, and ADHD. Conclusions：The adolescent psychiatric inpatients with a delinquent history presented with a certain clinical, family, psychometric characteristics that warrant specific clinical intervention strategies for their cognitive deficits, an impulsive personality style, family dysfunction with adverse life experiences and disruptive behavioral disorders, different from the rest of adolescent psychiatric inpatients.

• Journal of the Korea Concrete Institute
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• v.26 no.5
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• pp.573-579
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• 2014

Typical composite girder has been composed with conventional concrete deck and steel girder. Recently, ultrahigh-performance-concrete (UHPC) deck is proposed in order to enhance durability and reduce weight of deck as well as to increase stiffness and strength of the composite girder. This study investigates that a headed stud is still compatible as a shear connector for the UHPC deck and steel girder composite beam. Twelve push-out specimens are prepared to evaluate the static strength of stud shear connectors embedded in the UHPC deck. The test program proves that the static strength of the stud shear connectors embedded in UHPC well meets with design codes described in AASHTO LRFD. Chosen experimental variables are aspect ratio of height to diameter of stud, thickness of deck and thickness of concrete cover over the head of stud. From the test program, aspect ratio and cover thickness are investigated to mitigate the regulations of the existing design codes. The minimum aspect ratio and the minimum cover thickness given in AASHTO LRFD are four and 50mm, respectively. This limitation hinders to lower the thickness of the UHPC deck. The results of the experiment program give that the aspect ratio and the cover thickness can be lower down to three and 25mm, respectively. Eurocode-4 regulates characteristic relative slip at least 6mm. However, test results show that stud shear connectors embedded in UHPC provide the characteristic relative slip only about 4mm. Therefore, another measures to increase ductility of stud should be prepared.

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.543-555
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• 1997

Generally, in a steel-concrete composite gilder, the shear connector which was constructed between concrete deck and steel girder should have enough stiffness to behave as one body, because the conformity between plate and concrete deck is influences by the stiffness and spacing of the shear connectors. If the stiffness of shear connectors are insufficient, slip would happen at the contact surface. Partial interaction is the case that takes account of slips. In this paper, an easy method is presented to evaluate the stiffness or spacing of the shear connector according to the degree of imperfection without difficult calculations for a composite gilder with partial interaction. Also, the horizontal shearing force applied to the shear connector and the longitudinal axial force, which is occurs at contact surface between concrete deck and steel girder, have been presented in a simple influence line that is various to the parameters of sectional properties, degree of imperfection and applied load points. Furthermore, through the case study, it determined the relationships between the degree of imperfection and the follows 1) spring constants 2) axial force and horizontal shearing force 3) stress and neutral axis by using the partial differential equation based on Newmark's Partial Interaction Theory.

• CRM연구
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• v.2 no.2
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• pp.71-88
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• 2009

The purpose of this thesis is to examine the effects of e-CRM activities by the internet shopping mall companies on the purchase activities of purchase customers and the potential customers. The internet shopping companies utilize e-CRM to systematically identify customers' varying demands, and to utilize the results as marketing tools, thus producing a significant effect on the potential customers by generating customer feedback through e-Community. Contrary to their intention, however, cognitive dissonance can occur through e-Community, which may lead to customers' complaints. If these complaints are not properly managed and settled in a timely manner, they can be transferred to other potential customers, and the conformity phenomenon could be created by other complaining customers. Findings obtained through this thesis are as follows: If cognitive disharmony is created by customers who purchased products through the internet shopping malls, this can lead to private complaining behaviors, and subsequently, these behaviors are formed through e-Community. If the internet shopping mall companies do not take any timely and proper measures to intervene in the stage of private complaining behaviors in the first place, these behaviors will immediately escalate into the public complaining behaviors. Furthermore, the complaints will be transferred to other potential customers, ultimately resulting in their swift expansion. In other words, contrary to intention of the internet shopping mall companies, e-CRM does not facilitate the potential customers purchase decision, it rather affects them to postpone or withdraw their purchase decision. Accordingly, the internet shopping mall companies are required to manage e-Community with extreme care, and they should promptly respond to the complaining customers so that e-Community can function properly.

• Journal of Climate Change Research
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• v.9 no.4
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• pp.325-342
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• 2018

The Korea Emissions Trading Scheme ( K-ETS), which manages roughly 70% of the greenhouse gas emissions in South Korea, was initiated in 2015, after implementation of its 1st basic plan and the 1st allocation plan (2014) for the 1st phase (2015-2017). During the three and a half years since the launch of K-ETS, there have been critical policy change such as adjustment of the institutions involved, development and revision of the 2030 national GHG reduction roadmap, and change in the allocation plans. Moreover, lack of liquidity and fluctuation of carbon prices in the K-ETS market during this period has forced the Korean government to adjust the flexibility mechanism and auction permits of the market stability reserve. To evaluate the policy change in the K-ETS regarding conformance to its objectives, this study defines three objectives (Environmental Effectiveness, Cost Effectiveness and Economic Efficiency) and ten indicators. Evaluation of Environmental Effectiveness of K-ETS suggests that the national GHG reduction roadmap, coverage of GHG emitters and credibility of MRV positively affect GHG mitigation. However, there was a negative policy change implemented in 2017 that weakened the emission cap during the 1st phase. In terms of the Cost Effectiveness, the K-ETS policies related to market management and flexibility mechanism (e.g. banking, borrowing and offsets) were improved to deal with the liquidity shortage and permit price increase, which were caused by policy uncertainty and conservative behavior of firms during 2016-2018. Regarding Economic Efficiency, K-ETS expands benchmark?based allocation and began auction-based allocation; nevertheless, free allocation is being applied to sectors with high carbon leakage risk during the 2nd phase (2018-2020). As a result, it is worth evaluating the K-ETS policies that have been developed with respect to the three main objectives of ETS, considering the trial?and?error approach that has been followed since 2015. This study suggests that K-ETS policy should be modified to strengthen the emission cap, stabilize the market, expand auction-based allocation and build K-ETS specified funds during the 3rd phase (2021-2025).

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.393-405
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• 2020

The purpose of this study is to develop and validate a scale of vicarious trauma for sexual violence counselors. To this end, the concept of composition and preliminary questions of the vicarious trauma of sexual violence counselors were selected through the analysis of a content of individual interviews of sexual violence counselors and the precedent theory. Then, preliminary scale was developed after expert's evaluation of the validity of the contents. Next, as a result of a confirmatory factor analysis on the preliminary scale of 349 sexual violence counselors with experience in consulting sexual violence clients, it is confirmed that the conformity of five-factor structure was found to be favorable. As a result of convergent and discriminative validity analysis, it was confirmed that the developed scale is a reasonable tool for measuring vicarious trauma of sexual violence counselors by showing proper correlation with Secondary Traumatic Stress Scale, Counselor Burnout Inventory and Inventory of Countertransference Behavior. Furthermore, as a result of correlation analysis between professional identity and Belief in a Just World, it confirmed that it has predictive validity of the scale by indicating a high negative correlation. Furthermore, the relationship between the scale of vicarious trauma of sexual violence counselors and career background was analyzed. Finally, based on the results of this study, the significance and limitations of this study and the direction of future research were discussed.

• Journal of Global Scholars of Marketing Science
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• v.20 no.1
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• pp.27-34
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• 2010

During the past 10 years, sales of luxury goods increased significantly to more than US$ 130 billion in 2007. In this industry, more than half of the revenue comes from Asia where the average income has risen significantly, and the demand for luxury products is forecast to grow rapidly. Purchasing luxury brands appears to be an intriguing social phenomenon that is profitable for companies in this region. As a newly developed country, Korea is one of the most attractive luxury markets in Asia. Currently, a total of 120 luxury fashion brands have entered the Korean market, primarily in luxury districts in Seoul where the competition is fierce. The purposes of this study are to: (1) identify antecedents of attitude toward luxury brands, (2) examine the effect of attitudes toward luxury brands on customer equity, (3) determine the impact of attitudes toward luxury brands on customer lifetime value, and (4) investigate the influence of customer equity on customer life time value. Previous studies have examined materialism, social need, experiential need, need for uniqueness, conformity, and fashion involvement as antecedents of attitude toward luxury brands. Richins and Dowson (1992) suggested that that materialism influences consumption behavior relative to quantity of goods purchased. Nueno and Quelch (1998) reported that the ownership of luxury brands conveys information related to the owner's social status, communicates an image of success and prestige, and is a determinant of purchase behavior. Experiential need is recognized as an important aspect of consumption, especially for new products developed to meet consumer demand. Since luxury goods, by definition are relatively scarce, ownership of these types of products may fulfill consumers' need for uniqueness. In this study, value equity, relationship equity, and brand equity are examined as drivers of customer equity. The sample (n = 114) was undergraduate and graduate students at two private women's universities in Seoul, Korea. Data collection was conducted using a self-administered questionnaire survey in March, 2009. Data analysis included descriptive statistics, factor analysis, reliability analysis, and regression analysis using SPSS 15.0 software. Data analysis resulted in a number of conclusions. First, experiential need and fashion involvement positively influence participants' attitude toward luxury brands. Second, attitude toward luxury brands positively influences brand equity, followed by value equity and relationship equity. However, there is no significant relationship between attitude toward luxury brand and customer lifetime value. Finally, relationship equity positively influences customer lifetime value. In conclusion, young consumers are an important potential consumer group that tries different brands to discover the ones most suitable for them. Luxury marketers that use effective marketing strategies to attract and engender loyalty among this potentially lucrative consumer group may increase customer equity and lifetime value.