• Journal of the Korean Society for information Management
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• v.19 no.1
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• pp.23-46
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• 2002

With explosively increasing digital contents, library and Information center should have a new role between knowledge providers and knowledge users as information brokering organization. Electronic transaction system should be required for performing this brokering service since economic value is added to information and knowledge in information society. The developments and changes around library are keeping up with increasing building digital library and digitalizing printed sources. With the rapidly changing circumstances, the Internet is currently witnessing an explosive growth. By serving as a virtual information resource. the Internet can dramatically change the way business is conducted and Information is provided. However because of features o( the Internet like openness and information sharing, it has fundamental vulnerabilities in security issues. For Instance, disclosure of private information and line eavesdropping such as password, banking account, transaction data on network and so on are primary obstruction factors to activation of digital contents delivery on network. For high network security and authentication, this paper looks at smart card technologies and proposes multi-authentication protocol based on smart card on open network, implements and analyzes it.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.2
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• pp.91-101
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• 2006

Researches on services of vehicles have been mainly focused on how to provide useful information and entertainment for an in-vehicle driver. However, the needs are appreciably increased for more advanced services that help drivers to check and manage their vehicles conveniently, without requiring drivers to attach to their vehicles. It is a sort of ubiquitous computing, providing an intelligent interactive services for human at any time and any where. In this paper, we present an intelligent vehicle information system to enable a driver to remotely diagnose and control a vehicle via CDMA communication network connected to the Internet. The system improves mobility for diagnosis and control of vehicle by implementing a cut and call back mechanism, which allows the vehicle terminal to have access to the information server on the Internet via CDMA call. No matter where the driver is, he can obtain the remote diagnosis and control services on the web browser without any additional application installation. Design methodology is introduced and evaluation results are analyzed for the CDMA-based intelligent vehicle information system. The experimental results show that the response time of the vehicle terminal to a web client request is 10.302 seconds at the beginning and 646.44ms thereafter. The average response time of CAN sensor node to a vehicle terminal request is 6.669ms.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.23-28
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• 2016

In spite of various merit of algae as biofuel, the production cost of algae is a considerable obstacle for commercialization. The concurrent development of essential technologies is needed for the cultivating, harvesting, extracting and energy transformation. The production cost of algae biofuel has still higher than that of the other commercial biofuel. The major research activity has been focused on the cultivating and the research of other processes has been done with relatively lower activity. It is difficult to separate the algae from water because of the similar magnitude of density each other. The agglomeration and extracting of algae with the hybrid technology using ultrasonic wave is rare effect of environmental hazard and also it is appropriate technology for the next generation energy resources. The present research is investigated for the effective separation of algae from water with the ultrasonics wave. The aim of the present research is focused on the establishment of optimal design of algae agglomeration system. For this purpose, the computational fluid dynamic analysis has been conducted in the flow field with ultrasonic wave and algae flow to clarify the mechanism of algae separation by ultrasonic wave.

• Journal of the Korean GEO-environmental Society
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• v.13 no.1
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• pp.53-61
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• 2012

In this study, the research on MC anchor has been developed as composite type has done. MC anchor exerts bearing pressure on pre-bored hole where the end fixing device is expanded. Therefore, the uplift capacity is to be increased and it has the characteristics that the anchor body is not eliminated from the ground even if the grouting is not carried out properly. Furthermore, it reduces the loss of tension and raises the construction availability by inserting the reinforced bar as well as the anchor cable, while it can improve the long-term stability because the nail is expected to play the role when the loss of the anchor cable is occurred in a long-term. However, because the resistance mechanism of the compound anchor such as MC anchor is different from friction anchor, the estimation method of the uplift capacity by the frictional force of the ground and the grout is not proper. Particularly, in domestic cases, the problem to overestimate or underestimate the uplift capacity is expected because the design method considering the soil characteristics about the compound anchor has not been developed. Therefore, in this study, in order to evaluate the characteristics of MC anchor and a kind of compound anchor, we measured the uplift, the tension and the creep by nine anchors tests in shale ground that the fluctuation of the strength is great. In addition, we analyzed the test result comparing to the result of the general friction anchor and evaluated the characteristics of MC anchor movement to gather the results. As a result of the test, we found the effect that the uplift capacity is increased in shale ground comparing to the general friction anchor.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.12
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• pp.1071-1086
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• 2016

The safety of aircraft can be threatened by environmental factors, such as icing, turbulence, and lightning strike. Due to its adverse effects on aircraft structure and electronic components of aircraft, lightning strike is one of the biggest hazards on aircraft safety. Lightning strike can inject high voltage electric current to the aircraft, which may generate strong magnetic field and extreme hot spots, leading to severe damage of structure or other equipment in aircraft. In this work, mechanism of lightning strike and associated direct and indirect effects of lightning on aircraft were studied. First, on the basis of aircraft lightning regulations provided by Aerospace Recommended Practice (ARP), we considered different lightning waveform and zones of an aircraft. A coupled thermal-electrical computational model of ABAQUS was then used for simulating flow of heat and electric current caused by a lightning strike. A study on fuel tank, with and without lightning protection system, was also conducted using the computational model. Finally, electric current flow on two full scale airframes was analyzed using the EMA3D code.

• Journal of the Korean Institute of Gas
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• v.21 no.4
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• pp.70-75
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• 2017

This paper presents the FEM analysis results on the deformation behavior safety of automatic cut-off horizontal and conventional vertical gas valves. Based on the FEM analysis, the primary maximum deformation of $4.4{\mu}m$ was formed on the right end side of a valve body when the internal gas pressure was supplied on the screw port and gas discharge port of an automatic cut-off horizontal gas valve. And the secondary maximum deformation of $2.9{\mu}m$ was formed on the end side of safety valve port. This small deformation of an automatic cut-off horizontal gas valve is strongly related to the balanced design of a horizontal gas valve main body, which is composed of a screw part, gas outlet port, port for a stem and spindle shaft assembly, and safety valve port. But, the primary maximum deformation of 0.076mm was formed on the upper part of a conventional automatic cut-off vertical gas valve when the internal gas pressure was supplied on the screw port and gas discharge port. And the secondary maximum deformation of 0.055mm was formed on the left end side of a gas outlet port. This may effect on the sealing clearance of o-ring that is inserted on the groove of an automatic cut-off unit. Thus, this paper recommends an automatic cut-off horizontal gas valve compared with that of a conventional gas valve for a gas leakage free mechanism of a LPG cylinder valve.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1547-1554
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• 2017

VESTA (Verification of Ex-vessel corium STAbilization) and VESTA-S (-small) test facilities were constructed at the Korea Atomic Energy Research Institute in 2010 to perform various corium melt experiments. Since then, several tests have been performed for the verification of an ex-vessel core catcher design for the EU-APR1400. Ablation tests of an impinging $ZrO_2$ melt jet on a sacrificial material were performed to investigate the ablation characteristics. $ZrO_2$ melt in an amount of 65-70 kg was discharged onto a sacrificial material through a well-designed nozzle, after which the ablation depths were measured. Interaction tests between the metallic melt and sacrificial material were performed to investigate the interaction kinetics of the sacrificial material. Two types of melt were used: one is a metallic corium melt with Fe 46%, U 31%, Zr 16%, and Cr 7% (maximum possible content of U and Zr for C-40), and the other is a stainless steel (SUS304) melt. Metallic melt in an amount of 1.5-2.0 kg was delivered onto the sacrificial material, and the ablation depths were measured. Penetration tube failure tests were performed for an APR1400 equipped with 61 in-core instrumentation penetration nozzles and extended tubes at the reactor lower vessel. $ZrO_2$ melt was generated in a melting crucible and delivered down into an interaction crucible where the test specimen is installed. To evaluate the tube ejection mechanism, temperature distributions of the reactor bottom head and in-core instrumentation penetration were measured by a series of thermocouples embedded along the specimen. In addition, lower vessel failure tests for the Fukushima Daiichi nuclear power plant are being performed. As a first step, the configuration of the molten core in the plant was investigated by a melting and solidification experiment. Approximately 5 kg of a mixture, whose composition in terms of weight is $UO_2$ 60%, Zr 10%, $ZrO_2$ 15%, SUS304 14%, and $B_4C$ 1%, was melted in a cold crucible using an induction heating technique.

• Journal of Distribution Science
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• v.14 no.2
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• pp.113-121
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• 2016

Purpose - The purpose of this study is to identify team commitment affecting employees' innovative activities and factors affecting team commitment including empowerment by leaders and job enrichment factors. In other words, so as to explain outcome variables of innovative activities, this study aims to emphasize employees' attachment roles towards their groups within nomological network, and identify the motives encouraging employees' innovative activities. The research purpose is significant due to the realistic situation of hotel industry. The reason why innovative activities are important can be found in recent changes of business environment. Also, unlike other various studies on precedence factors encouraging employees' innovative activities, this study classified those precedence factors into job and leader characteristics, and it emphasized the importance of team commitment as the process that job and leader characteristics are connected to innovative activities. Research design, data and methodology - The survey for this study was conducted during October 6^th ~ November 10^th in 2014 to the employees who are working in 5-star hotels in Korea. As for the selection of hotels and sampling method, convenience sampling method was used to the employees in 5-star hotels. Self-report method was used in the survey, judging that the employees' characteristics would be relatively homogeneous. 311 questionnaires were distributed in total, and 275 reponses were collected. After excluding the missing and unreliable responses, 245 questionnaires were used in the research. SPSS and AMOS programs were used for the analysis. Results - First, empowering leadership had positive effects on hotel employees' team commitment. It indicates that hotel employees are more committed to their team when their leaders set examples, provide information, and involve employees in decision-making process. Second, as a result of the relationship analysis in task diversity, task significance, task identity and team commitment, task diversity and task significance had significant effect on team commitment, while task identity had no significant effect on team commitment. It indicates that team commitment is enhanced when the employees can conduct diverse types of jobs and get more opportunities to talk with the guests. Also, the repetition for the same jobs in hotel rooms and the space for preparing food and beverage do not lead to team commitment, even though the employees fulfill their duties to the end. Third, hotel employees' team commitment has positive effect on their innovative activities. It indicates that employees voluntarily conduct innovative activities when they are attached to their team and identifies themselves with the team. Conclusions - There are theoretical and practical implications in this study. First, in terms of the theoretical perspective, this study proposes structural framework in team commitment, and it identifies the psychological mechanism in team commitment from the aspect of social exchange, which resulted in identification of precedence factors related to team commitment. In addition, this study presents new possibilities for relevant studies about team commitment by examining the effect on team commitment when the importance of innovative activities is emphasized in recent business environment.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.4
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• pp.29-41
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• 2014

The Korean government has purchased land properties alongside any significant water bodies before setting up the buffers to secure water qualities. Since the annual budgets are limited, however, there has always been the issue of which land parcels ought to be given the priority. Therefore, this study aims to develop efficient mechanism for land acquisition priorities in stream corridors that would ultimately be vegetated for riparian buffer zones. The criteria of land acquisition priority were driven through literary review along with experts' advice. The relative weights of their value and priorities for each criterion were computed using the Analytical Hierarchy Process(AHP) method. Major findings of the study are as follows: 1. The decision-making structural model for land acquisition priority focuses mainly on the reduction of non-point source pollutants(NSPs). This fact is highly associated with natural and physical conditions and land use types of surrounding areas. The criteria were classified into two categories-NSPs runoff areas and potential NSPs runoff areas. 2. Land acquisition priority weights derived for NSPs runoff areas and potential NSPs runoff areas were 0.862 and 0.138, respectively. This implicates that much higher priority should be given to the land parcels with NSPs runoff areas. 3. Weights and priorities of sub-criteria suggested from this study include: proximity to the streams(0.460), land cover(0.189), soil permeability(0.117), topographical slope(0.096), proximity to the roads(0.058), land-use types(0.036), visibility to the streams(0.032), and the land price(0.012). This order of importance suggests, as one can expect, that it is better to purchase land parcels that are adjacent to the streams. 4. A standard scoring system including the criteria and weights for land acquisition priority was developed which would likely to allow expedited decision making and easy quantification for priority evaluation due to the utilization of measurable spatial data. Further studies focusing on both point and non-point pollutants and GIS-based spatial analysis and mapping of land acquisition priority are needed.

• Journal of Korean Academy of Nursing
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• v.29 no.5
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• pp.1087-1102
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• 1999

Diabetes mellitus, a universal and prevalent chronic disease, is projected to be one of the most formidable worldwide health problems in the 21st century. For those living with diabetes, there is a need for self-care skills to manage a complex medical regimen. Self-efficacy which refers to one's belief in his/her capability to monitor and perform the daily activities required to manage diabetes has be found to be related to self-care. The concept of self-efficacy comes from social cognitive theory which maintains that cognitive mechanism mediate the performance of behavior. The literature cites several research studies which show a strong relationship between self-efficacy and self-care behavior. Meta-analysis is a technique that enables systematic review and quantitative integration of the results from multiple primary studies that are relevant to a particular research question. Therefore, this study was done using meta-analysis to quantitatively integrate the results of independent research studies to obtain numerical estimates of the overall effect of a self-efficacy with diabetic patient on self-care behaviors. The research proceeded in three stages : 1) literature search and retrieval of studies in which self-efficacy was related to self-care, 2) coding, and 3) calculation of mean effect size and data analysis. Seventeen studies which met the research criteria included study population of adults with diabetes, measures of self-care and measures of self-efficacy as a predictive variable. Computation of effect size was done on DSTAT which is a statistical computer program specifically designed for meta-analysis. To determine the effect of self-efficacy on self-care practice homogeneity tests were conducted. Pooled effect size estimates, to determine the best subvariable for composite variables, metabolic control variables and component of self-efficacy and self-care, indicated that the effect of self-efficacy composite on self-care composite was moderate to large. The weighted mean effect size of self-efficacy composite and self-care composite were ＋.76 and the confidence interval was from ＋.66 to ＋.86 with the number of subjects being 1,545. The total for this meta-analysis result showed that the weighted mean effect sizes ranged from ＋.70 to ＋1.81 which indicates a large effect. But since reliabilities of the instruments in the primary studies were low or not stated, caution must be applied in unconditionally accepting the results from these effect sizes. Meta-analysis is a useful took for clarifying the status of knowledge development and guiding decision making about future research and this study confirmed that there is a relationship between self-efficacy and self-care in patients with diabetes. It, thus, provides support for nurses to promote self-efficacy in their patients. While most of the studies included in this meta-analysis used social cognitive theory as a framework for the study, some studies use Fishbein & Ajzen's attitude model as a model for active self-care. Future research is needed to more fully define the concept of self-care and to determine what it is that makes patients feel competent in their self-care activities. The results of this study showed that self-efficacy can promote self-care. Future research is needed with experimental design to determine nursing interventions that will increase self-efficacy.