• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1903-1911
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• 2016

As interest in MANET is increasing nowadays, research upon an efficient MANET routing protocol is actively under way. A LQA(Link Qualty Aware)-AODV routing protocol to deal with frequent changes of topology and wireless link variations under tactical operating conditions is proposed in this paper. The suggested LQA-AODV takes into account the channel capacity of each hop during the route request process of the traditional AODV protocol. In detail, LQA-AODV adds a channel capacity cost value to the RREQ message format that occurs during the routing process of the existing AODV Routing Protocol causing the accumulated channel capacity cost values of each sections to be compared before establishing a route. To verify the performance of LQA-AODV, NS2.35 was utilized and the Link-Quality Model was applied in order to reflect the tactical wireless environment. The simulation compares and analyzes LQA-AODV and the existing AODV, showing a large improvement over the traditional AODV in regards to the Packet Delivery Ratio, and End-to-End Delay.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.155-165
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• 2012

This essay talks about research of robust design for quality improvement of production procedure of Wet Etchant. It suggested the optimum design method in consideration of specific capability value that is the way to maximize the quality of product in the production system by using Daguchi parameter design method while finding factors affecting product quality with analysis of production system of product A from producer D. Also, it set long term of 6months as noise factor and let it to be the robust design that can find the optimum condition of control factor that is dull to the changes of each month, that is the change in noise factor. The control factor which affects the product quality is decided as combination method, temperature of raw material, combination time and as there are too many possibilities for combination methods, we performed 4 methods first based on previous research data then derived three ways with product that passed SPEC and set as the factor. As a result of application of optimum production procedure suggested in this essay to the actual production process with its standardization, there was a effect of drop of more than 10particles in comparison to the particle number of previous product and also it brought the effect that resulted the stable number of particle of under 30 that is what the client company suggested.

• The Journal of the Convergence on Culture Technology
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• v.4 no.4
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• pp.219-225
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• 2018

This study was conducted to see if a correlation between social support, self-efficacy and quality of life of stroke patients. The study sample was composed of 60 stroke patients who participated in the rehabilitation hospital in G-city and P-city. The survey period for data collection was from August 8.1 - October 10.1, 2017. social support, self-efficacy and quality of life of stroke were administered to those patients. Among the sum of social support, self-efficacy and quality of life marks, a significant correlation was shown statistically at all levels. Through this study, it shows a solid data base is necessary for the improvement of cognitive function in elderly stroke patients.

• Journal of the Korean institute of surface engineering
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• v.44 no.1
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• pp.21-25
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• 2011

This test focuses on the correlation between the lubrication, ductility and strength through the change of nut lubricant which decides joining angle for A490 bolt sets required in the AASHTO (American Association of State Highway & Transportation Officials). Because the lubrication of high tension bolt, nut, washer sets becomes an important factor to ductility and joining load, the quality improvement is required for improving reliability and securing enough lubrication of maker and user. This study examines the quality characteristics required in the specification through tests because only this standard specifies joining quality in the extreme conditions (as much about two times of the joining angle on site as normal condition). Moreover, this study is limited to the test on joining axial force required in the AASHTO for the three nut lubrication conditions of A490 bolt set. It is concluded that the nuts should be coated or waxed enough for the improvement of the joining axial force and ductility of bolts required in the standards. It is shown that in the case of plain high tension bolt sets, a rust preventing lubricative oil shall be applied and the torque coefficient value for A490 bolt sets should be maintained below 0.175.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.614-621
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• 2010

A indigenous freshwater bivalve Unio douglasiae was introduced to compare the differences in the efficacy of algal bloom control and the appearances of mussel-mediated adverse effects between two different reservoirs such as mesotrophic (Shingu r.) and hypertrophic (Seokmun r.). We constructed the study mesocosm in the shore of each reservoir, stocked the mussel at density of $30indiv./m^3$ for 7 days, and measured daily the phytoplankton density and water quality. In mesotrophic reservoir, even though approximately 38% of suspended solids and chlorophyll-a was reduced by stocked bivalves for the first 3 days, algal density, ammonia and soluble reactive phosphorus gradually increased with increasing mussel death. In hypertrophic reservoir, mussels strongly inhibited suspended solids and chlorophyll-a by the termination of study with no increase of mussel death and nutrient, especially ammonia concentration. In both reservoirs, a strong selectivity showed mussels preferred to diatom rather than cyanobacteria and green algae without algal density and nutrient level. Our results indicate that an introduction of freshwater bivalve U. douglasiae is more strategic to improve water quality of hypertrophic than mesotrophic reservoir, but many preliminary studies on the treatment method and the selection of target water system are required.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.266-270
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• 2010

In case of the Dental X-ray apparatus, the diameter (or the field size) of the tip of the cone should be less than 7 cm according to the Diagnosis Radiation Equipment Safety Management. However, deviation from the field is not expected to be big as photography is made at close range from the skin. Also, as the size of film or digital detector used in intra-oral photography is $3\times4cm^2$, the size mentioned above can be considered to be much bigger. Furthermore, the patient dose by short-distance photography can not be ignored. Therefore, effect on the patient dose, resolution and image qualty was examined by reducing the cone diameter by 0.5 cm interval. The result showed that the patient dose was reduced and a partial improvement in picture contrast was observed. Therefore, it can be concluded from these results that further investigation may be worthwhile in terms of policy.