• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.2
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• pp.14-23
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• 1998

The present study investigates numerically particle laden flow through compressor cascade. In general, a lot of turbine engines are affected by various particles which are suspending in the atmosphere. Especially in the case of aircraft aviating in volcanic, industrial and desert region including many particles, each components of engine system are damaged severely. That damage modes are erosion of compressor binding and rotor path components, partial or total blockage of cooling passage and engine control system degradation.. Initial damages can not be serious but cumulation of damages influences on safety of aircraft control and economical maintenance cost of engine system can be increased. When dust, materials and volcanic particles in the atmosphere flow in the compressor, it is necessary to predict damaged and deposited region of compressor blades. To the various flow inlet angle, predictions of particles trajectory in compressor cascade by Lagrangian method are presented and impulses by impaction of particles at blade surface are calculated. By the definition of particle deposition efficiency, characteristics of particles impact are considered quantitatively. With these prediction and experimental data, erosion rates are predicted for two materials - ceramic, soft metal - on compressor blade surface. Improvements like coating of blade surface could be found, by above prediction.

• Journal of KIISE
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• v.43 no.12
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• pp.1428-1436
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• 2016

A multipath routing in wireless sensor networks (WSNs) provides advantage such as reliability improvement and load balancing by transmitting data through divided paths. For these reasons, existing multipath routing protocols divide path appropriately or create independent paths efficiently. However, when the sink node moves to avoid hotspot problem or satisfy the requirement of the applications, the existing protocols have to reconstruct multipath or exploit foot-print chaining mechanism. As a result, the existing protocols will shorten the lifetime of a network due to excessive energy consumption, and lose the advantage of multipath routing due to the merging of paths. To solve this problem, we propose a multipath creation and maintenance scheme to support the mobile sink node. The proposed protocol can be used to construct local grid structure with restricted area and exploit grid structure for constructing the multipath. The grid structure can also be extended depending on the movement of the sink node. In addition, the multipath can be partially reconstructed to prevent merging paths. Simulation results show that the proposed protocol is superior to the existing protocols in terms of energy efficiency and packet delivery ratio.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.1
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• pp.27-38
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• 2009

The multi-level profile system is designed to measure the vertical profile of $H_2O$ and $CO_2$ concentrations in the surface layer to estimate the storage effects within the plant canopy. It is suitable for long-term experiments and can be used also in advection studies for estimating the spatial variability and vertical gradients in concentration. It enables the user to calculate vertical fluxes of water vapor, $CO_2$ and other trace gases using the surface layer similarity theory and to infer their sources or sinks. The profile system described in this report includes the following components: sampling system, calibration and flow control system, closed path infrared gas analyzer(IRGA), vacuum pump and a datalogger. The sampling system draws air from 8 inlets into the IRGA in a sequence, so that for 80 seconds air from all levels is measured. The calibration system, controlled by the datalogger, compensates for any deviations in the calibration of the IRGA by using gas sources with known concentrations. The datalogger switches the corresponding valves, measures the linearized voltages from the IRGA, calculates the concentrations for each monitoring level, performs statistical analysis and stores the final data. All critical components are mounted in an environmental enclosure and can operate with little maintenance over long periods of time. This report, as a practical manual, is designed to provide helpful information for those who are interested in using profile system to measure evapotranspiration and net ecosystem exchanges in complex terrain.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.495-501
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• 2003

Impaction is defined as the cessation of the eruption of the tooth caused by a clinically or radiographically detectable physical barrier in the eruption path or by the ectopic position of tooth germ. Besides the third molars and the maxillary canines, the most common impacted tooth is the second premolar. The overall frequency of premolar impaction has been reported to be 0.5%. In some cases, orthodontic traction and surgical repositioning may be indicated. When impacted second premolar is involved with prolonged retained second primary molar, extraction of primary molar and space maintenance lead to eruption of second premolar. In these cases, all patients visited to department of pediatric dentistry of Kyungpook National University Hospital for the chief complaint of unerupted second premolar. Extraction of prolonged retained second primary molar and space management are tried for spontaneous eruption of impacted second premolar tooth. The results were as follows: 1. When impacted second premolar is involved with prolonged retained second primary molar, minimal treatment via elimination of primary molar leads to successful results. 2. Proper space management and periodic radiographic examination are required before eruption of second premolar. 3. Sufficient time must be allowed for confirm of tooth movement before orthodontic traction or surgical repositioning. 4. The result is more successful in incomplete root development.

• Spatial Information Research
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• v.20 no.6
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• pp.33-43
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• 2012

As part of recent sustainable transport, bike has come into the spotlight as a green transport at close range to link between walking and public transit and also alterative to solve problems of existing vehicle travel. Some arguments on promotion of using bicycles have already been made in Europe, the U.S and other developed countries. To be sure, much has been written extensively in description of utilization of bike oriented by supplier, for examples, Level of Service with bike path, infrastructure such as bicycle racks and lounge etc. Therefore, our study has been differentiated in development of new evaluation model focused on level of bike user's satisfaction, comprehensively considering suitability for bikeway installation, connectivity of the public transportation system and stability in Incheon City. ANP(Analytic Network Process) analysis which is able to allow consideration of the interdependence of criteria has been hired due to multi-collinearity instead of AHP used in multi-criteria decision analysis. Last but not least, we drew bike route on a case-by-case for maintenance and improvement of its facility in Namdong-gu and Bupyeong-gu. To conclude, suggested finding has dem onstrated the validity of evaluation scheme for bikeways which is appropriate for type and purpose and ultimately this can be used to establish policy decision making for improvement of bikeway.

• The Journal of the Korea Contents Association
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• v.14 no.10
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• pp.506-513
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• 2014

As a measure to overcome the limit of small city which is weak in spontaneous competitiveness and to improve the quality of environmental, cultural and economic life of dwellers, it analyzed the geographical characteristics of city, movement path, economic status and other simple problems comprehensively and produced the vague problem solutions for dwellers and the practical direction for design using the 3D simulation rendering in order to suggest the result to change the potential for urban policy into substantial alternative. Geochang-gun selected as research area is evaluated for the place with high symbolic value of bridge in terms of environment, and the new design development for this kind of public design can be the good measure to increase the competitiveness of the city. This research is to understand the direction of the bridge recreation project which provides the cultural space connecting with other areas and improves the competitiveness of small city and to suggest the appropriate bridge design in order to provide the reasonable maintenance direction related to the future development of public design and the achievement of the symbolism of the region and to suggest the examples of public design for the urban competitiveness. For this purpose, focusing on Wicheon-stream in Geochang County, Gyeongsangnam-do selected as the research and development area for bridge design, it is to design the concept design bridge newly emphasizing the symbolism of bridge-oriented city for the development of future city.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6A
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• pp.355-367
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• 2012

Many of old aqueduct bridges located in rural areas are in need of repair and redesign. They still occupy some portion of countryside landscaping. However, most of them were designed to fulfill their basic functions of carrying waters, which has not contributed to the landscape positively. Moreover, it is not rational to treat each design case of aqueduct bridges individually because they are relatively small in size and arranged continuously over a long path. Therefore, it is better to provide a design guideline to repair or to redesign old aqueduct bridges as a whole considering both structural safety and landscape. The main objective is to develop a framework to repair and redesign of old aqueduct bridges for safety improvement and better landscape. Specifically this paper will address the development of possible design alternatives for repair and redesign The development of design alternatives for redesign will follow general principle of bridge aesthetics and be represented according to structural system, flume shape, pier height, pier shape in terms of design parameters while minor repair includes paintings and other ornamentations. And the developed design alternatives will be reviewed with its landscape as a background to check the visual compatibility within the community context. It is expected that the proposed guideline will be utilized to develop a maintenance plan to revitalize old aqueduct bridges to improve overall landscape of rural areas.

• Journal of Distribution Science
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• v.11 no.4
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• pp.51-60
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• 2013

Purpose - The objective of this paper is to investigate the effect of asset specificity, the level of information sharing, the importance of information sharing, and an integrated collaborative environment on supply chain performance. Research design, data, and methodology - Data collection was implemented as follows: questionnaires were distributed to 250 companies that have business ties with Halla Climate Control Corporation. The empirical study to test our hypothesis was based on statistical analysis (using SPSS 18.0 and AMOS 18.0). The hypothesis of this paper is that the asset specificity variable has positive effects on the following variables: Level of information sharing, the importance of information sharing, and integrated collaborative environment. Moreover the variables, the level of information sharing, and the importance of information sharing are strongly influenced by the variable integrated collaborative environment, and these when combined, have an effect on the dependent variable, supply chain performance. We tested our hypothesized model utilizing path analysis with latent variables. Results - According to the results of our analysis, hypothesis H1, which tests whether there is a relationship between asset specificity and the integrated collaborative environment, is supported at the 0.01 level. Hypotheses H2 and H3 were also confirmed, and asset specificity had positive effects (+) on the level of information sharing variable. The importance of the information sharing variable was statistically significant at the 0.01 level. Hypotheses H4 and H5 posited that the integrated collaborative environment variable would have a positive effect on the level of information sharing; the importance of information sharing variable was strongly supported statistically, with a significant p-value below. Moreover, the level of information sharing (H6), and the importance of information sharing (H7) variables also had a statistically relevant influence on supply chain performance. As a result, existence of a collaborative system between companies would influence supply chain performance by strengthening real-time information access and information sharing. Thus, it is important to construct a collaborative environment where information sharing among companies and cooperation is possible. Conclusions - First, with rapid changes in the business environment, it becomes necessary for enterprises to acquire the right information in order to properly implement SCM. For successful SCM, firms should understand the importance of collaboration with supply chain partners and an internally built collaboration system, which in turn will better promote a partnership commitment with suppliers as well as collaborative integration with buyers. A collaborative system, as we suggest in this paper, facilitates the maintenance of a long-term relationship of trust, and can help reinforce information sharing. Second, it is necessary to increase information sharing over time via a collaborative system so that employees of the suppliers become aware of the system. The more proactive and positive attitudes are towards such a collaborative system by the managerial group, the higher the level of information sharing will be among the users. Successful SCM performance is achieved by information sharing through a collaborative environment rather than by investing only in setting up an information system.

• Journal of Distribution Science
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• v.11 no.1
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• pp.25-34
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• 2013

Purpose - This study examines the adverse press coverage that has increased in proportion to the remarkable growth of various kinds of franchise businesses in the food service industry. Today, the trust of franchisees in relation to their franchisor, and the maintenance of good relations between the two, has become a significant social issue. This study investigates relationship satisfaction and the long-term commitment between the franchisor and franchisee. Research design, data, methodology - We used a path analysis to investigate the relationship between justice and trust, trust and relationship satisfaction, justice and relationship satisfaction, trust and long-term commitment, and relationship satisfaction and long-term commitment. Structural Equation Modeling and a Sobel test were used to investigate the mediating effects of trust and relationship satisfaction. Data were collected from 237 Food Franchisees in Seoul and Gyeonggi Province in order to test the theoretical model and its hypotheses. Two research methodologies are generally used in the distribution management field. For this study, an empirical method was used. Results - A causal analysis was carried out to test if the research model has a sufficient fit index (for instance, χ² = 46.694, df = 10, p = .000, GFI = 0.946, AGFI = 0.850, RMR = 0.034, NFI = 0.966, CFI = 0.973), and the results showed that the model was sufficient, thus demonstrating the suitability of the research model. Each hypothesis had a positive influence, both on long-term commitment and relationship satisfaction. Justice with the franchisor had a positive influence on trust. Relation satisfaction cognized by franchisees was found to positively influence long-term commitment. The franchisee perception of justice in relation to the franchisor had no significant influence on long-term commitment. The study investigated the hypothesis that trust could mediate justice and long-term commitment, and that relationship satisfaction could also mediate long-term commitment Both trust and relationship satisfaction were found to be important for long-term commitment. Specifically, trust sub-factors and justice sub-factors influenced long-term commitment. Identification-based and knowledge-based trust were more important than calculus-based trust. Distributive justice was deemed more important than procedural justice; distributive justice should thus be strengthened. Conclusions - Both franchisor and franchisee were independent businesses. Evidently however, the franchisor could not ensure profit without long-term commitment from the franchisee. As for the success of the franchise business, the franchisor should carry out appropriate strategies leading to a satisfactory relationship. For example, transparency makes it possible to maintain and enhance trust and to improve relationship satisfaction. Just relations between franchisor and franchisee should make it possible to maintain and enhance the franchisee's trust. The franchisor should provide a variety of information with respect to the franchisee's business success. Finally, in order to improve the franchisee's long-term commitment, the franchisor should ensure a just approach with trust and relationship satisfaction among their strategies.

• Journal of Korean society of Dental Hygiene
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• v.4 no.1
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• pp.65-79
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• 2004

There are two purposes in this study. The first one is to collect some oral health information through the investigations upon the oral health care of Korean adults. Referring to the result of the investigation. I wanted to furnish fundamental data with oral health education for each age and with a publicity booklet editing. That is the second purpose of this research. Among the people who visited Seo-gu Public Health Center in Kwang-ju, 207 people answered the questionnaires. There were 86 men and 121 women from the 20-aged to the 59- aged. The questionnaires covers knowledge aquisition path for dental caries prevention, the cognition degrees for the causes of dental caries and its prevention, the cognition degrees for the causes of periodontal disease and its prevention, the degrees for oral health methods, and the importance of oral health. The conclusions are as follows; 1. The cognition degree for dental caries prevention: The cognition for pit and fissure sealant was appeared most highly in thirties by 85.3%. but 62.1 % in fifties was answered, "Never heard". The cognition degree for fluoride application was appeared most highly in thirties by 73.5%. and the cognition degree for water fluoridation was most highly in forties by 54.2%. 2. The knowledge for pit and fissure sealant was acquired mostly through dental hospital in every age by 54.2%. 3. The knowledge for fluoride application was learned mostly through dental hospitals in twenties and thirties by 32.7%. and mostly through TV or radio health programs in forties and fiftieseach by 35.7% and 50.0%. 4. The knowledge for water fluoridation was acquired through TV or radio programs in all ages such as twenties. thirties. forties and fifties. Its rate was 57.8%. 5. The cognition degree of the cause of dental caries: 53.1 % of all ages think that dental caries can most frequently be caused by being lack of toothbrushing. 6. The cognition degree of the cause of periodontal disease: 58.5% people of all ages think that both dental plaque and calculus might be the main cause of periodontal disease. 7. The cognition degree of dental caries prevention: 72.8% people think that dental caries can be prevented by right tooth brushing method. and 8.7% people think that they can be prevented by scaling. However, 10.7% people of them were not interested in dental caries prevention. 8. The importance of oral health: 35.3% people think that teeth health is the most important, and 63.8% people think oral health is one of the most important health problems. Forties answered that tooth health was the most important thing, and fifties. thirties and twenties followed in the order. 9. The cognition for oral health maintenance: all ages(twenties. thirties. forties. and fifties) answered that right toothbrushing method was the best way to keep oral health by 69.1%.