• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.943-951
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• 1992

The objectives of this study are to analyse the thermal response behavior occurring in the charring ablative material more realistically by considering ablation and char phenomena occurring in several material layers, and to increase the reliability of thermal analysis by being able to get stable solutions through using the finite analytic method. A program has been developed to predict the temperature distribution, ablation thickness, char thickness, ablation velocity and char velocity by solving non-linear one-dimensional heat conduction equation. Results of calculation were compared with results of published papers. From this compariosn this program was proved to be a very good tool for thermal design and analysis of charring ablative materials used in the rocket propulsion system.

• Structural Engineering and Mechanics
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• v.65 no.3
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• pp.291-302
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• 2018

Rigid body spring method (RBSM) is an effective tool to simulate the cracking process of structures, and has been successfully applied to investigate the behavior of reinforced concrete (RC) members. However, the theoretical researches and engineering applications of this method mainly focus on two-dimensional problems as yet, which greatly limits its applications in actual engineering projects. In this study, a three-dimensional (3-D) RBSM for RC structures is proposed. In the proposed model, concrete, reinforcing steels, and their interfaces are represented as discrete entities. Concrete is partitioned into a collection of rigid blocks and a uniform distribution of normal and tangential springs is defined along their boundaries to reflect its material properties. Reinforcement is modeled as a series of bar elements which can be freely positioned in the structural domain and irrespective of the mesh geometry of concrete. The bond-slip characteristics between reinforcing steel and concrete are also considered by introducing special linkage elements. The applicability and effectiveness of the proposed method is firstly confirmed by an elastic T-shape beam, and then it is applied to analyze the failure processes of a Z-type component under direct shear loading and a RC beam under two-point loading.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.9
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• pp.467-475
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• 2020

The study aims to investigate factors affecting enterprise's satisfaction and loyalty toward the Social Security's online public services, looking at the case of Thanh Hoa province, Vietnam. This study employs samples with 216 enterprises that use online public system of Thanh Hoa province's Social Security. The research model is closely linked to the SERVQUAL model developed by Parasuraman, Zeithaml and Berry (1988). We propose 23 scales that constitute the quality of service, three scales that constitute Customer Satisfaction and three components that constitute Customer Loyalty. This study use the tool of Exploratory Factor Analysis (EFA), Cronbach's Alpha test, Confirm Factor Analysis (CFA) and Structural Equation Modeling (SEM) in order to address the question of satisfaction and loyalty. The result shows that the factor with the most impact is Reliability, next is Capacity of staffs, Tangibles, Attitude of staffs, and the least impacting factor is Empathy; moreover, the results also show that Satisfaction has a strong impact on Customer Loyalty. The findings of this study suggest that Thanh Hoa province's Social Security should: (i) strengthen the reliability of online service system; (ii) build capacity for staffs; (iii) develop the responsiveness of electronic transactions systems; and (iv) improve the empathy of staffs.

• Journal of Nutrition and Health
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• v.32 no.3
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• pp.296-306
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• 1999

This study was carried out to prepare a copper database of Korean foods which can be used in calculating copper intake from dietary data, and to evaluate the copper nutritional status of Koran adults living in rural areas by dietary intake and serum copper concentrations. A copper database for 1,176 Korean foods was constructed (1) by analysing 112 Korean foods which are frequently consumed by Korean adults living in rural areas, (2) by adapting values form food composition databases from other countries-320 items from the University of Minnesota database, 201 items from the USAD database, and 25 items from U.K. database, and (3) by imputing values from similar foods for 518 food items. Copper intake of 2,034 Korean adults over the age of 30 living in Yeonchongun was Kyunggi province, Korea was estimated by 24-hour recall method. Mean daily copper intake of subjects was 0.98mg. Mean daily intake level of males was 1.11mg which was significantly higher than that of females, 0.88mg. There was a significant difference in the distribution of subjects by the level of copper intake and sex(p<0.05). Mean serum copper concentration was 14.8umol/1 and the percentage of subjects with low, adequate, and high levels of copper concentration were 23.9%, 69.4%, and 6.6%, respectively. The two food groups which contributed most to the dietary copper intake of subjects were cereals and grain products, and vegetables, supplying 46.2% and 12.7% of total copper intake, respectively. Individuallym, rice contributed most, suppling 31% of total copper intake, followed by soybean curd, starch vermicle, barley, etc. Plant foods contributed to 82.1% of the total copper intake. In summary, results of this study show that copper intake of Korean adults living in rural areas is low, and that dietary sources of copper are mainly plant foods. Serum levels of copper in the subjects were relatively normal. The copper database for Korean foods constructed in present study will be a valuable tool for the as-yet limited assessment of copper intake of Koreans. Such studies will contribute to the establishment of a dietary of a dietary allowance of copper and the relationship of copper nutriture and chronic diseases in Koreans.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.365-372
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• 2004

LNGC suffers a great heat inflow during navigation and this heat inflow inevitably boils off the LNG. The boiled off gas(BOG) is normally consumed as a fuel for ship's engine. The boiled off LNG means a loss of cargo during transportation in the viewpoint of shipper. Therefore, a contract between shipper and ship operator is made for the limitation of BOR under 0.15 ％/day based on laden voyage. This contract on BOR limit requires that ship's officer has a correct knowledge on BOR for his ship. nut, in most cases ship IS operated based on only officer's experiences. In this study, author presented a simple model to predict the BOG during navigation based on the existing precision heat exchange design technology about the heat distribution on the hull and heat inflow from outside through the hull. The BOG is calculated for ballast and laden voyage based on the actual weather conditions and verified by comparing with the measured BOG for the study ship. The study ship is a membrane type LNGC which is now servicing in Middle east route. Thus, the BOG prediction method which is presented in this study is expected to be used for an useful tool to manage the BOG in now servicing LNGC.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.9
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• pp.1179-1184
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• 2018

Korean travel agencies that have been utilizing the Internet passively feel threatened as global online travel agencies are quickly permeating the Korean travel market. Under these circumstances, this study conducted a focused analysis on how ICT affects the business environment of travel agencies. Based on the analyzed data, it also presents coping strategies for the Korean travel agencies. First, it is imperative to accelerate platform development to counteract the distribution structure of global tourism products. Second, it is essential that travel agencies actively utilize big data, the new paradigm of technology where data are generated at high speed, high volume, and for numerous purposes. Third, it is necessary to actively utilize a travel blog marketing strategy. As a communication tool for travel agencies, the continuing development of the Internet highlights the usefulness of marketing activities using blogs. Finally, it is essential to provide each customer more specialized travel consultancy.

• The KIPS Transactions:PartA
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• v.8A no.2
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• pp.133-146
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• 2001

In a dynamic load distribution policies, each node gathers the current system sates information before making a decision on load balancing. Load balancing policies based on this strategy can suffer from processor thrashing. In this paper, we propose a new algorithm which attempts to decrease the frequency of the processor thrashing, the algorithm is based on the integration of three components. The first, the algorithm of which determine the size of jobs be transferred. The second, negotiation protocol with obtains a mutual agreement between a sender and a receiver on the transferring job size. And the third, a symmetrically-initiated location policy. The algorithm proposed in this paper used Siman IV as simulation tool to prove the improvement of performance. I analyzed the result of simulation, and compared with related works. The mean response time shows that there are no difference with existing policy, but appear a outstanding improvement in high load. The thrashing coefficient that shows the average response time, CPU overhead and the thrashing ratio at both the receiving and sending node has been used in the analysis. A significant improvement in the average response time and the CPU overhead ratio was detected using our algorithm when an overhead occurred in the system over other algorithm. The thrashing coefficient differed in the sending node and the receiving node of the system. Using our algorithm, the thrashing coefficient at the sending node showed more improvement when there was an overhead in the system, proving to be more useful. Therefore, it can be concluded that the thrashing ratio can be reduce by properly setting the maximum and minimum value of the system’s threshold queue.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.127-131
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• 2007

This study was designed to demonstrate the ability of Texas Eye Research and Technology Center Dry Eye Questionaire (TERTC-DEQ) to examine the distribution of self-reported dry eye symptoms and their diurnal intensity in university students and compare it with McMonnies & Ho DEQ. Two dry eye questionnaires were administered to 46 contact lens wearers and 47 nonwearers. Contact lens wearers scored higher on the TERTC-DEQ (52.2%) than McMonnies & Ho DEQ (6.5%). Non-contact lens wearers also scored higher on the TERTC-DEQ (19.1%) than McMonnies & Ho DEQ (2.1%). Ocular symptoms worsened with progression of time of day in both groups of subjects. This study suggests that TERTC-DEQ provides a first-choice diagnosis tool to obtain a comprehensive assessment of patient's symptoms, especially in comparison with McMonnies & Ho DEQ. The TERTC-DEQ is an efficient screening survey and may be use in dry eye diagnosis of contact lens-related dry eye.

• International Journal of Fluid Machinery and Systems
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• v.2 no.4
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• pp.353-362
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• 2009

In the process of turbine modernizations, the investigation of the influences of water passage roughness on radial flow machine performance is crucial and validates the efficiency step up between reduced scale model and prototype. This study presents the specific losses per component of a Francis turbine, which are estimated by CFD simulation. Simulations are performed for different water passage surface roughness heights, which represents the equivalent sand grain roughness height. As a result, the boundary layer logarithmic velocity profile still exists for rough walls, but moves closer to the wall. Consequently, the wall friction depends not only on roughness height but also on its shape and distribution. The specific losses are determined by CFD numerical simulations for each component of the prototype, taking into account its own specific sand grain roughness height. The model efficiency step up between reduced scale model and prototype value is finally computed by the assessment of specific losses on prototype and by evaluating specific losses for a reduced scale model with smooth walls. Furthermore, surveys of rough walls of each component were performed during the geometry recovery on the prototype and comparisons are made with experimental data from the EPFL Laboratory for Hydraulic Machines reduced scale model measurements. This study underlines that if rough walls are considered, the CFD approach estimates well the local friction loss coefficient. It is clear that by considering sand grain roughness heights in CFD simulations, its forms a significant part of the global performance estimation. The availability of the efficiency field measurements provides an unique opportunity to assess the CFD method in view of a systematic approach for turbine modernization step up evaluation. Moreover, this paper states that CFD is a very promising tool for future evaluation of turbine performance transposition from the scale model to the prototype.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.4
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• pp.403-405
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• 1984

Since chlorella was found to be a source of protein in 1974, wide ranges of investigations on culture methods, its constituents and nutritional factors have been carried out, i. e. most of them were the reports on the nutritional evaluation. However, kinetics such as absorption, distribution, metabolism and elimination of chlorella protein have not been fully elucidated. So, on the assumption that using $N^{15}$ labelled chlorella protein could accomplish good results for kinetics of chlorella in in vivo experiments, $N^{15}$ was added to the culture fluid. From the result of this study, it is suggested that chlorella utilizes N as well as $N^{15}$ in protein synthesis, and this $N^{15}$ labelled chlorella protein can be useful tool for the study of kinetics of chlorella in in vivo experiments.