• Korean Journal of Construction Engineering and Management
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• v.15 no.5
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• pp.94-102
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• 2014

This study analyzes necessity of expanding construction insurance and estimates required budget. Construction insurance is obliged by National Contract Law and Local Contract Law to protect projet owners and contractors from any unexpected construction risk such as financial losses in construction process. Currently the contracts of design-build and alternate-bid projects as well as PQ project, which are greater than 20 billion won, require the contractors to provide construction insurances in Korea. Insurance premiums are borne by the public project owner. Those contractors whose contract volume is less than 20 billion won burden all risks of projects at their cost. This causes equity problem. Because small-and-medium contractors are discriminated against large contractors since insurance-obliged projects are performed by large contractors and insurance premiums are borne by the public project owner. On the other hands, in all engineering projects, regardless of volume, insurance premiums are borne by the project owner. Therefore current regulation has to be improved, by expanding to all public projects. The average ratio of unobliged projects is 46%, in recent 3 years, prime cost of insurance companies is estimated 0.2%. Moreover considering risks of each construction type, prime cost of unobliged works is estimated as 0.13%. Hence additional necessary budget is estimated to be 2.09 billion won if total volume of public work is 3.5 trillion won. And 2.39 billion won is derived if total volume of public projects is 4 trillion won.

• Journal of Mushroom
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• v.14 no.2
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• pp.64-69
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• 2016

Pleurotus eryngii is one of the most widely cultivated and important edible mushrooms. However, the shelf life of the fruiting body is short, which. To solve this problem, a new cultivar, DanBi 5Ho, of Pleurotus eryngii was developed by mono-mono crossing between monokaryotic strains derived from KNR2598 and KNR2610. The optimum temperature formycelial growth was 25 and that forfruiting body development was 15-16. The quality did not change after a period of 40.0 d at 4. This result was significantly different compared to that ofthe control strain Knneuari 2 Ho. Analysis of genetic characteristics of the new hybrid strain DanBi 5Ho revealeda different profile thanthat of the parental and control strains when random amplification of polymorphic DNA (RAPD) primers we used. The results obtained from this study show that DanBi 5Ho is a new hybrid strain, characterized by improved storability after harvesting.

• Journal of Korea Water Resources Association
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• v.49 no.6
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• pp.481-493
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• 2016

The statistical analysis to the torrential rainfall data that is defined as a rainfall amount more than 80 mm/day is performed with Daegu and Busan rainfall data which is collected during 384 months. The number of occurrence of the torrential rainfall events can be simulated usually using Poisson distribution. However, the Poisson distribution can be frequently failed to simulate the statistical characteristics of the observed value when the observed data is zero-inflated. Therefore, in this study, Generalized Poisson distribution (GPD), Zero-Inflated Poisson distribution (ZIP), Zero-Inflated Generalized Poisson distribution (ZIGP), and Bayesian ZIGP model were used to resolve the zero-inflated problem in the torrential rainfall data. Especially, in Bayesian ZIGP model, a informative prior distribution was used to increase the accuracy of that model. Finally, it was suggested that POI and GPD model should be discouraged to fit the frequency of the torrential rainfall data. Also, Bayesian ZIGP model using informative prior provided the most accurate results. Additionally, it was recommended that ZIP model could be alternative choice on the practical aspect since the Bayesian approach of this study was considerably complex.

• Tunnel and Underground Space
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• v.24 no.6
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• pp.449-463
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• 2014

There are many case studies and application cases in abandoned mines for hydraulic filling method filled by slurry or paste form, but research on the pneumatic filling is not applied in Korea. The damage of steel pipe is occurred by wear due to the flow of filling material in the bent area of steel pipe in traditional pneumatic filling method. In this study, the new pneumatic filling method was developed using a newly devised improved nozzle to improve the above problem. The model test for mine filling was performed in the laboratory for the simulated accessible or inaccessible mine cavities, and the filling efficiency by the results obtained from the test was calculated. The filling efficiency was analyzed from the variation of outlet angle, feed rate and grain size of sand in model test of simulated accessible mine cavity. The superiority of improved pneumatic filling method was proved through the analysis of filling efficiency by the results obtained from each model tests of gravitational, traditional, and improved filling method in simulated inaccessible mine cavity.

• Journal of the Korean GEO-environmental Society
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• v.13 no.11
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• pp.61-68
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• 2012

Most widely methods for reinforcement of soil utilized in Korea are anchor method, soil nail method and micro pile method. These methods are classified by the intended use of the structure to be constructed, but the reinforcement of the ground is accomplished contains in common the process of grouting work after inserting the reinforcements. Domestically, gravity grouting has been used mostly so far, but there has always been the risk of insufficient restoration of the loose ground area from the drill holes because the grouting is conducted only by gravity. On the other hand, pressure reinjection grouting may enhance the grouting quality by solving the problem of the existing grouting method considerably since it additionally reinjects grouting through pre-installed tube a certain time after the first grouting. Accordingly, this study evaluated the pullout characteristics by the grouting methods by performing model test on decomposed granite soil, and investigated the support increasing characteristics of reinforcements depending on the curing time, reinjection pressure, and uplift force variation of the pressure reinjection grouting. The result of this research shows that the pressure reinjection grouting demonstrated 1.1~1.3 times of performance of the gravity grouting, and suggests some analysis on optimal water content, reinjection pressure and curing time of the pressure reinjection grouting.

• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.79-89
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• 2013

Recently, the need for outsourcing sensitive data has grown due to the wide spreading of cost-effective and flexible cloud service. However, there is a fundamental concern in using such service since users have to trust external servers. Therefore, searchable encryption can be a very valuable tool to meet the security requirements of data outsourcing. However, most of work on searchable encryption focus only on privacy preserving search function and relatively lacks research on encryption mechanism used to actually encrypt data. Without a suitable latter mechanism, searchable encryption cannot be deployed in real world cloud services. In this paper, we analyze previously used and possible data encryption mechanisms for multi-user searchable encryption system and discuss their pros and cons. Our results show that readily available tools such as broadcast encryption, attribute-based encryption, and proxy re-encryption do not provide suitable solutions. The main problem with existing tools is that they may require separate fully trusted servers and the difficulty in preventing collusion attacks between outsiders and semi-trusted servers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.1938-1945
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• 2014

This study intends to investigate physical trauma in the adolescent during exercise of teenage elite judo players in Seoul. The subjects were male 67, female 14, totally 81 in middle and high school student and the data collected june the first to 28th, 2013. A data were analyzed frequency analysis, chi-square test and t-test using SPSS 16.0 program. The questionaire was contained 6 categories, experience, region, types, time, causes, intervention and preventionof sports injury. The highest results of each categories of this study is that experience of injury is 77(95.1%), region is knee 35(70.0%), type is contusion 42(54.5%), time is summer 54(70.1%), cause is body crash 40(51.9%), and intervention is going hospital 46(59.7%). To prevent physical trauma, we should recognize physical trauma durind exercise as a health problem. And to prevent physical trauma, relatives should make prevention prorgram for adolescent sports players. It will improve their quality of life.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11A
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• pp.878-891
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• 2011

We consider the throughput-maximization problem for both the up- and downlink in a wireless network with interference channels. For this purpose, we design an iterative and distributive uplink algorithm based on Lagrangian relaxation. Using the uplink power prices and network duality, we achieve throughput-maximization in the dual downlink that has a symmetric channel and an equal power budget compared to the uplink. The network duality we prove here is a generalized version of previous research [10], [11]. Computational tests show that the performance of the up- and downlink throughput for our algorithms is close to the optimal value for the channel orthogonality factor, ${\theta}{\in}$(0.5, 1]. On the other hand, when the channels are slightly orthogonal (${\theta}{\in}$(0, 0.5]), we observe some throughput degradation in the downlink. We have extended our analysis to the real downlink that has a nonsymmetric channel and an unequal power budget compared to the uplink. It is shown that the modified duality-based approach is thoroughly applied to the real downlink. Considering the complexity of the algorithms in [6] and [18], we conclude that these results are quite encouraging in terms of both performance and practical applicability of the generalized duality theorem.

• Journal of Korea Water Resources Association
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• v.44 no.10
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• pp.777-786
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• 2011

In the previous researches for storm sewer design, the flow path, pipe diameter and pipe slope were determined to minimize the construction cost. But in the sewer networks, the flows can be changed according to flow path. The current optimal sewer layout models have been focussed on satisfying the design inflow for sewer designs, whereas the models did not consider the occurrences of urban inundation from excessive rainfall events. However, in this research, the sewer networks are determined considering the superposition effect to reduce the inundation risk by controlling and distributing the inflows in sewer pipes. Then, urban inundation can be reduced for excessive rainfall events. An Optimal Sewer Layout Model (OSLM) was developed to control and distribute the inflows in sewer networks and reduce urban inundation. The OSLM uses GA (Genetic Algorithm) to solve the optimal problem for sewer network design and SWMM (Storm Water Management Model) to hydraulic analysis. This model was applied to Hagye basin with 44 ha. As the applied results, in the optimal sewer network, the peak outflow at outlet was reduced to 7.1% for the design rainfall event with 30 minutes rainfall duration versus that of current sewer network, and the inundation occurrence was reduced to 24.2% for the rainfall event with 20 years frequency and 1 hour duration.

• Journal of Nutrition and Health
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• v.44 no.6
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• pp.498-506
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• 2011

This study examined the relationship among plasma homocysteine, folate, and vitamin $B_{12}$ levels and neurocognitive function in 118 community-dwelling elderly subjects (mean age, $75.1{\pm}6.7$ years). The Mini-Mental State Examination (MMSE-KC) was used to screen and assess neurocognitive function in the participants. Dietary intake data including the use of dietary supplements were obtained using the 24-hour recall method by well-trained interviewers. Plasma folate and vitamin $B_{12}$ concentrations were analyzed by radioimmunoassay, and homocysteine was assessed by a high performance liquid chromatography-fluorescence method. The proportions of participants with suboptimal levels of plasma folate (< 3 ng/mL), vitamin $B_{12}$ (< 221 pmol/mL), and homocysteine (> $15{\mu}mol/L$) were 16.1%, 5.9%, and 21.2%, respectively. A multiple regression analysis showed that plasma homocysteine was negatively associated with plasma folate and vitamin $B_{12}$ levels. The MMSE-KC test scores were significantly associated with plasma homocysteine and folate, but not with vitamin $B_{12}$, after adjusting for age, gender, body mass index, living with spouse, education, current smoking, energy intake, and chronic diseases such as hypertension, diabetes, thyroid disease, dyslipidemia, stroke, and cardiovascular disease. A general linear model adjusted for covariates revealed that MMSE-KC test scores increased from the lowest to the highest quartiles of vitamin $B_1$, vitamin $B_2$, vitamin $B_6$, vitamin $B_{12}$, and vitamin C intake (p for trend = 0.012, 0.039, 0.014, 0.046, 0.026, respectively). These results indicate that the problem of folate inadequacy and hyperhomocysteinemia are highly prevalent among community-dwelling elderly people and that dietary intake of the B vitamins and vitamin C is positively associated with cognitive function scores.