• Resources Recycling
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• v.29 no.1
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• pp.53-61
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• 2020

This study aimed to develop a foam concrete material for a ground repair system that has low strength and low fluidity by using an eco-friendly binder, which substitutes industrial by-products for more than 90% of cement. Basic properties were evaluated after substituting a small amount of calcium sulfo aluminate (CSA) for the binder to improve the sinking depth rate and volume change, commonly found when it had a large amount of industrial by-products. The substitution rates of CSA for the eco-friendly binder used for the foam concrete were 2.5, 5, and 10%. Fresh properties, hardened properties, pore structure, and hydrates were analyzed. Experimental results showed that using only 2.5% of CSA could improve the deep sinking depth which occurred when using an eco-friendly binder. As a result, the weight difference between the upper, middle, and lower parts of cast specimens was improved even after being hardened. The addition of CSA also contributed to the formation of small, uniformly sized closed pores and improved initial strength. However, when the proportion of CSA increased, the long-term strength decreased. However, it satisfied the target strength when 5% or less of CSA was used. The results of this study revealed that it was possible to manufacture foam concrete with low strength and high fluidity for repairing ground satisfying target qualities by adding 2.5% of CSA to the eco-friendly binder containing a large amount of industrial by-products.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.10
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• pp.651-660
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• 2013

Object oriented design brought up improvement of productivity and software quality by adopting some concepts such as inheritance and encapsulation. However, both the number of software's classes and object couplings are increasing as the software volume is becoming larger. The object coupling between classes is closely related with software complexity, and high complexity causes decreasing software quality. In order to solve the object coupling issue, IT-field researchers adopt a component based development and software quality metrics. The component based development requires explicit representation of dependencies between classes and the software quality metrics evaluates quality of software. As part of the research, we intend to gain a basic data that will be used on decomposing software. We focused on properties of the linkage between classes rather than previous studies evaluated and accumulated the qualities of individual classes. Our method exploits machine learning technique to analyze the properties of linkage and predict the strength of dependency between classes, as a new perspective on analyzing software property.

• Journal of Navigation and Port Research
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• v.32 no.6
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• pp.499-503
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• 2008

As the conference result of MEPC in IMO, development of ballast water management system corresponding to newly established ballast water management standard (D2 regulation) of shipping is being made an active progress over the whole world. The ballast water management system should treat particular material of more than $10{\mu}m$ in high capacity of more than 500t per hour in the event of filtration process. Also, it is very difficult to develop a practical management system since a limited element which a narrow space of the ship should be designed in the minimal volume is assumed. Therefore, the study promoted a study on the next generation auto back wash media filter to overcome such a limited element. Also, the study performed pressure and flux measurement test followed by thickness of each filter medium for filtration by each size to grasp a relation between absorption and pressure at the time of vacuum filtration and mechanical analysis and turbidity change observation of filtered water after vacuum filtration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.882-887
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• 2001

The purpose of this study was to investigated quality properties of breads prepared from wheat flour with persimon leaf power. Results showed that the volume of bread was lessened, the weight of bread went up, and baking loss rate diminished as persimmon leaf powder content incremented. The experiment showed that bread was maintained in the low level of springiness and cohesiveness was relatively reduced as time lapsed, whereas 3.0 and 5.0% test group remained significantly high level. There was a rapid increment in chewiness and gumminess, which tended to show significantly low as compared to control group, Results of sensory evaluation showed that the preference scores decreased as the persimmon leaf powder contents increased (p<0.05), flavor made no significant differences up to 3.0% test group, however, 5.0% test group containing elutionsuch as catechin or tannin produced sour and bitter taste so strongly that made if feel uncomfortable with. The augment of content indicated a low prederence in terms of texture, in an overall preference had no significant differences as compared to the control group, and 0.5% test group. Through the results of these of these experiments, we can conclude that the highest quality of persimmon leaf powder content is no more than 0.5% in making bread added with persimmon leaf powder.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.95-106
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• 2005

Road accidents are considered as the result of a complex interplay between road, vehicle, environments, and human factors. Little study, however, has been carried out on the attributes of human factor compared to the road geometric conditions and traffic conditions. The previous researches focused on mainly both traffic and geometric conditions on specific location. Therefore, it's hard to explain phenomenon of the high traffic accident rates where road and traffic conditions are good. Because of these reasons, accident analysis has contributed on geometric improvement and has not contributed on traffic management such as selection of attention section, driver napping alert, etc. The freeway incident management is also associated with reliable prediction of incident occurrences on freeway sections. This paper presents a method for estimating the effect of trip length on freeway accident rate. A PAR (Potential Accident Ratio), the new concept of accident analysis, considering TLFDs (Trip Length Frequency Distributions) is suggested in this paper. This approach can help to strengthen freeway management and to reduce the likelihood of accidents.

• Journal of agriculture & life science
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• v.46 no.5
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• pp.127-136
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• 2012

This study examined antioxidative activities and quality characteristics of noodle produced with the pine needle powder as 0.5, 1.0 and 2.0% (v/v to korean wheat powder). DPPH radical scavenging activity, reducing power, antioxidative activities, tyrosinase inhibitory activity of the solvent fraction extracts increased in a dose-dependent manner. Especially, butanol fraction showed high DPPH radical scavenging activity, reducing power, antioxidative activities and tyrosinase inhibitory activity. The weight, volume, water absorption and turbidity of cooked noodles containing pine needle powder increased as pine needle powders were higher. When the amount of pine needle powder increased, the Hunter L (lightness) and a (redness) value of cooked noodles decreased, but b (yellowness) value increased. The texture of noodle containing pine needle powder have decreased than control using only Korean wheat powder in hardness, cohesiveness, springiness, gumminess and chewiness. The results of sensory evaluation of cooked noodles containing pine needle powder indicated that the cooked noodles with 1.0% pine needle powder showed the highest value.

• FLOWER RESEARCH JOURNAL
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• v.16 no.2
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• pp.134-142
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• 2008

This work aims to obtain basic information for seed propagation of Hydrangea serrata for. acuminata. The germination percentage of the seeds taken on 15 November, 30 December, and 23 January was $90.0{\pm}4.16%$, $84.4{\pm}5.52%$, and $88.9{\pm}2.40%$, respectively. This suggest that seeds of Hydrangea serrata for. acuminata are non-dormant seeds. The optimum temperature for germination was $25^{\circ}C$ and light was necessary. Most of the growth parameters (shoot and leaf length, stem diameter, root length, no. of roots, T/R ratio, and fresh and dry wts.) were significantly greater at $25/20^{\circ}C$ and $25^{\circ}C$ than at the other temperatures. Low T/R ratio at relatively cool temperatures (15 and $20^{\circ}C$) was caused by suppressed top growth. In light quality treatment, red light (RL) significantly enhanced stem elongation. The greatest photosynthetic pigments (total chl, chl a/b, and carotenoid) were observed in seedlings grown in blue light (BL), followed by seedlings grown in RL+BL. When blue light was added, higher pigment contents were found. Effect of plug cell size (50, 72, 128, 162 and 200 cells) on the growth of seedlings was investigated. The highest top growth was observed in seedlings grown in 50 cell trays, followed by seedlings grown in 72, 128, 162, and 200 cell trays. However, there was no significant differences between 162 and 200 cell trays. Especially, smaller size leaves were observed in seedlings grown in smaller cell trays (lower volume and high plant density).

• Journal of the Korean Electrochemical Society
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• v.22 no.4
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• pp.155-163
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• 2019

Mixture electrodes of a graphite having a good cycle performance and a silicon monoxide (SiO) having a high capacity are fabricated and their cycle performances are evaluated as negative electrodes for lithium-ion batteries. The electrode prepared by mixing the natural graphite and carbon-coated SiO in a mass ratio of 9:1 shows a reversible capacity of $480mAh\;g^{-1}$, 33% higher than that of graphite. However, the capacity deteriorates continuously upon cycling due to the volume change of silicon monoxide. In this study, the factors that can improve the cycle performance have been discussed through the change in the configurations of the electrode and the electrolyte. The electrode using the carboxymethyl cellulose (CMC) binder shows the best cycle performance compared to the conventional binders. The electrode sing the CMC and styrene-butadiene rubber (SBR) binder not only has almost the similar cycle characteristics with the electrode using the CMC binder but also has the better rate capability. When the fluoroethylene carbonate (FEC) is used as an electrolyte additive, the cycle life is improved. However, the electrolyte with 5 wt% of FEC is appropriate because the rate capability decreases when the content of FEC is increased to 10 wt%. In addition, when the mass loading of the electrode is lowered, the cycle performance is greatly improved. Also, enhanced cycle performance is achieved using the roughened Cu current collector polished by abrasive paper.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.373-379
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• 2019

Polymethyl methacrylate (PMMA), a self-polymerizing resin for removable orthodontic devices, has been used as a dental orthodontic device for many years because of its advantages such as color stability, volume stability, and tissue compatibility. However, such a removable orthodontic device has a disadvantage that the longer the use in the oral cavity due to the low strength of the PMMA fracture of the orthodontic device resin in use. In this study, zinc nanoparticles (ZNP) were mixed with orthodontic PMMA to introduce strength effect. Rectangular samples ($1.4{\times}3.0{\times}19.0mm$) of orthodontic PMMA (0, 0.5, 1.0, 2.0 and 4.0%) containing ZNP were prepared. The finished specimen was tested for three-point bending strength at a speed of 1 mm / min, and the Vickers hardness was measured three times using a hardness tester. The surface roughness was measured with a surface roughness. As a result, the 3-point bending strength did not change significantly (p>0.05). Surface energy increased significantly. As a result, we successfully synthesized ZNP in this study and prepared the dispersed resin specimen for calibration. It will be possible to develop high-density dental orthodontic resins.

• Journal of Korea Port Economic Association
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• v.34 no.3
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• pp.133-158
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• 2018

The role and ratio of national vessels in the global container shipping market have reduced significantly due to the bankruptcy of Hanjin Shipping in early 2017. All import-export companies, as well as container ports in Korea, are facing a crisis. The Trump's tariff and trade battles have had a negative impact on the increase in the North American cargo. However, Chinese and Japanese container shipping companies, which merged with domestic container shipping companies, and mega carriers such as Maersk and CMA CGM have benefited from the decline in shipping supplies due to the collapse of Hanjin Shipping, the world's 10th largest container carrier in Korea. The import/export freight trade in Korea is witnessing the increasing stronghold of foreign carriers. This scenario is expected to weaken Korea's negotiation powers with overseas shipping companies in domestic ports, such as Busan and Kwangyang, thereby making it more challenging to attract shipping carriers. This study compares the global container-shipping network in 2007 and 2017 by combining the network topology of the social network analysis and the economics of the liner shipping connectivity index (LSCI) and the container port connectivity index (CPCI) analysis. The findings of this study are that the role of the ports across the world can be identified, and CPCI has a high correlation with the centrality index and freight volume data. These findings can contribute toward the utilization of the meaning of the necessary centrality index without an additional centrality analysis. This study can be applied not only to the call strategy of container carriers but also to the alliance and development strategy of Korean ports.