• The Journal of Korean Academy of Prosthodontics
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• 제41권3호
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• pp.288-299
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• 2003

Statement of problem: Many kinds of post and core systems are in the market, but there are no clear selection criteria for them. Purpose: The purpose of this study was to compare the flexural strength and modulus of elasticity of core materials, and measure the bending strength of post systems made of a variety of materials. Material and Methods: The flexural strength and elastic modulus of thirteen kinds core buildup materials were measured on beams of specimens of $2.0{\times}2.0{\times}24{\pm}0.1mm$. Ten specimens per group were fabricated and loaded on an lnstron testing machine at a crosshead speed of 0.25mm/min. A test span of 20 mm was used. The failure loads were recorded and flexural strength calculated with the measured dimensions. The elastic modulus was calculated from the slopes of the linear portions of the stress-stram graphs. Also nine kinds commercially available prefabricated posts made of various materials with similar nominal diameters, approximately 1.25mm, were loaded in a three-point bend test until plastic deformation or failure occurred. Ten posts per group were tested and the obtained data were anaylzed with analysis of variance and compared with the Tukey multiple comparison tests. Results: Clearfil Photo Core and Luxacore had flexural strengths approaching amalgam, but its modulus of elasticity was only about 15% of that of amalgam. The strengths of the glass ionomer and resin modified glass ionomer were very low. The heat pressed glass ceramic core had a high elastic modulus but a relatively low flexural strength approximating that of the lower strength composite resin core materials. The stainless steel, zirconia and carbon fiber post exhibited high bending strengths. The glass fiber posts displayed strengths that were approximately half of the higher strength posts. Conclusion: When moderate amounts of coronal tooth structure are to be replaced by a post and core on an anterior tooth, a prefabricated post and high strength, high elastic modulus core may be suitable. CLINICAL IMPLICATIONS In this study several newly introduced post and core systems demonstrated satisfactory physical properties. However when the higher stress situation exists with only a minimal ferrule extension remaining a cast post and core or zirconia post and pressed core are desirable.

• Informatization Policy
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• 제18권3호
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• pp.88-107
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• 2011

This paper proposes a prepaid system promotion policy for the 3G(WCDMA) MVNO with regard to the newly included paragraphs 3, 4 and 5 of Article 32 (User Protection) and Article 38 (Provision of Wholesale Telecommunications Services) of the Telecommunication Business Act, which was revised on March 22, 2010. As of June 2011, there are only a few prepaid system subscribers to the mobile communications service due to various limitations, including prepay, interconnection, carrier selection, the MVNO policy, and number portability. However, overseas communications service regulatory agencies and service providers are increasingly presenting policies and strategies for mobile prepaid plans, in order to accommodate the various customer demands that are increasing the use of smart phones and data. This paper advances various proposals concerning promotion of the prepaid system by the 3G MVNO under the current Telecommunication Business Act, including separation of the prepaid data system and the mobile network; introduction of a monthly fixed-rate hybrid prepaid system, a top-up system and USIM system; introduction of mobile network carrier selection; differentiated retail discounts between prepaid and post-paid prices; revision of the retail discount policy for wholesale provision; increase in the number of mandatory service providers; and in-depth consideration of the introduction of a number portability policy for the prepaid and post-paid systems.

• Journal of Navigation and Port Research
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• 제46권3호
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• pp.216-226
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• 2022

The industry trends of major global shipping and ports in the world are changing rapidly because of the spread of COVID-19, resulting in the reorganization of GVCs by global companies, and strengthening of environmental regulations by IMO. Based on these environmental changes, Busan Port was ranked 5th in the global container port rankings in 2013. However, since the outbreak of COVID-19, Busan Port's global container port ranking in 2020 fell to 7th, behind Qingdao Port. In the post-Corona era, for Busan Port to compete with global container ports and gain a competitive edge in the port, it is necessary to accurately identify the competitive factors of Busan Port and establish a comprehensive policy. Thus, the purpose of this study was to analyze how the competitive factors of Busan Port have changed in the selection of ports by current global shipping companies, compared to the first study conducted in 2005. Additionally, a comprehensive policy plan was established by identifying factors impacting the frequency of future calls as well as the growth potential of Busan Port, through a stepwise multiple regression analysis. As a result of the analysis, it was found that the call preference and growth potential of Busan Port in the post-Corona era are most affected by 'port facilities'. And it was found that the calls frequency in the future is most impacted by 'the geopolitical location' factor.

• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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• pp.116-123
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• 2003

Forages are the most important feed resource for ruminants worldwide, whether fed as pastures, forage crops or conserved hay, silage or haylage. There is large variability in the quality of forages so measurement and prediction of feeding value and nutritive value are essential for high levels of production. Within a commercial animal production system, methods of prediction must be inexpensive and rapid. At least 50% of the variation in feeding value of forages is due to variation in voluntary feed intake. Identification of the factors that constrain voluntary feed intake allows these differences to be managed and exploited in forage selection. Constraints to intake have been predicted using combinations of metabolic and physical factors within the animal while simple measurements such as the energy required to shear the plant material are related to constraints to intake with some plant material. Animals respond to both pre- and post-ingestive feedback signals from forages. Pre-ingestive signals may play a role in intake with signals including taste, odour and texture together with learned aversions to nutrients or toxins (post-ingestive feedback signals). The challenge to forage evaluation is identification of the factors which are most important contributors to these feedback signals. Empirical models incorporating chemical composition are also widely used. The models tend to be useful within the ranges of the datasets used in their development but none can claim to have universal application. Mechanistic models are becoming increasingly complex and sophisticated and incorporate both feed characteristics and use of biochemical pathways within the animal. Improvement in utilisation through the deliberate selection of pasture plants for high feeding value appears to have potential and has been poorly exploited. Use of Near Infrared Reflectance Spectroscopy is a simple method that offers significant potential for the preliminary screening of plants with genetic differences in feeding value. Near Infrared Reflectance Spectroscopy will only be as reliable as the calibration sets from which the equations are generated.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제30권5C호
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• pp.398-405
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• 2005

The multiuser detection (MUD) based wireless receiver requires more accurate channel estimation than the single user detection (SUD) schemes such as Rake receiver, and hence the post processing is required for MUD to clean up the estimated channel coefficients by eliminating the noise only coefficients. The adaptive post processing method is proposed in order to provide more accurate channel responses and the power level of the background noise and interferences at the cost of the negligible processing delay compared to the conventional method based on the threshold test with the threshold value relative to the noise variance. The simulations are performed in 3GPP-TDD mode environment. The results show that the noise estimation error of the proposed method is maximum $10\%$, which is much smaller than $50\%$ maximum error of the conventional method.

• The Journal of the Korea Contents Association
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• 제14권7호
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• pp.242-252
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• 2014

This research examined whether there are differences in group decision making between senior leader groups and junior leader groups. Results revealed that senior leaders contributed more during the discussion than junior leaders, and groups with senior leaders performed better than the groups with junior leaders. In post-discussion activities group members noted that senior leaders were able to represent their groups better, and showed better leadership during discussion. On the other hand, the leader's age impacted differently depending on leader selection methods. For senior leaders, leaders randomly assigned were perceived to be more beneficial to groups. However for junior leaders, leaders systematically selected were perceived to represent their groups better and exhibit better leadership. The interaction between leader's age and leader selection seems to arise from a difference of leader's power bases.

• The Journal of the Korea Contents Association
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• 제20권2호
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• pp.215-225
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• 2020

In selecting a company of A-E service provider for a public construction project, public owners make widely use the evaluation method based on the quantitative criteria to emphasize transparency and fairness instead of putting more weighting on bidders' technical capability. The selection method and process to select technically better company has been in discussion to motivate company to build up their technical capability and better quality of service. This paper examined US laws and regulations related to evaluating and selecting an A-E company for public construction project in terms of principles, process, selection committee, evaluation methods, and contract management and so on. Then deduced several implications for domestic public owner to select the most adequate company for a certain architectural service through fair and efficient way. The major findings are technical capability based selection, emphasizing owner's role and responsibility, consideration of small and mid-sized company, debriefing, and post-service evaluation.

• Archives of Plastic Surgery
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• 제42권6호
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• pp.729-734
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• 2015

Background Insufficient satisfaction outcome literature exists to assist consultations for scar revision surgery; such outcomes should reflect the patient's perspective. The aim of this study was to prospectively investigate scar revision patient satisfaction outcomes, according to specified patient-selection criteria. Methods Patients (250) were randomly selected for telephone contacting regarding scar revisions undertaken between 2007-2011. Visual analogue scores were obtained for scars pre- and post-revision surgery. Surgery selection criteria were; 'presence' of sufficient time for scar maturation prior to revision, technical issues during or wound complications from the initial procedure that contributed to poor scarring, and 'absence' of site-specific or patient factors that negatively influence outcomes. Patient demographics, scar pathogenesis (elective vs. trauma), underlying issue (functional/symptomatic vs. cosmetic) and revision surgery details were also collected with the added use of a real-time, hospital database. Results Telephone contacting was achieved for 211 patients (214 scar revisions). Satisfaction outcomes were '2% worse, 16% no change, and 82% better'; a distribution maintained between body sites and despite whether surgery was functional/symptomatic vs. cosmetic. Better outcomes were reported by patients who sustained traumatic scars vs. those who sustained scars by elective procedures (91.80% vs. 77.78%, P=0.016) and by females vs. males (85.52% vs. 75.36%, P<0.05), particularly in the elective group where males (36.17%) were more likely to report no change or worse outcomes versus females (16.04%) (P<0.01). Conclusions Successful scar revision outcomes may be achieved using careful patient selection. This study provides useful information for referring general practitioners, and patient-surgeon consultations, when planning scar revision.

• Journal of Chest Surgery
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• 제30권8호
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• pp.827-832
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• 1997

Lung volume reduction surgery(LVRS) has recently been advocated as an alternative or a bridge to lung transplantation for patients with evere dibbling emphysema. This procedure is a palliative treatment performed to alleviate the dyspnea of patients with emphysema and improve performance in the activities of daily living. The rationale of lung volume reduction for generalized emphysema is that the removing of the diseased and functionless lung may improve the function of remaining, less diseased lung. The factors critical to the success of LVRS are careful patient selection, accurate localization of target areas, meticulous anesthetic and operative technique, and intensive postoperative support. We have experienced a case of severe emphysema in a 59-year-old male patient. After selection process and pulmonary rehabilitation, the patient was treated with video-assisted thoracoscopic LVRS and the post-operative course was uneventful.

• Hwankyungkyoyuk
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• 제20권1호
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• pp.90-105
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• 2007

The purpose of this study is to find the influence of environmental issue analysis instruction on the environmental decision making ability for grade 5 elementary school students. The study was done through pre and post testing control group structure. The object of this study is grade 5 of I elementary school students which were divided into 35 student test group and 54 student control group. Through studying references, the selection standard of appropriate environment issue and the environmental issue analysis instructing objective. Conducted the environment issue instructing based on the selected environment issue and instructing objective. The classes were held in total of 6 sessions in the chapters related to class objective and class content within the curriculum. The pre and post testing was done using environment decision making ability test sheet which was reconstructed by myself and the results were analyzed by t-test. As a result of comparing pre and post testing the students in test group showed significant results in the processes of problem recognition, evaluation of alternatives, behave planing (p<.001). As a result of comparing the differences of environment decision making ability of pre and post test of test group and control group, it showed significant results in the process of evaluation of alternatives(p<.00l). The environment issue analysis class has positive influence on the environment decision making abilities of the students but since the outcome of environment decision making ability is lower, there is a need for long term environment education plan and further studies to find whether the environment issues within the textbook is appropriate in the elementary student level, useful school aspect and the influence of environment issue analysis class on the change of values for individuals.