• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.130-135
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• 2008

An aerodynamic optimization design process of multistage axial turbine is presented in this article: first, applying quasi-three dimensional(Q3D) design methods to conduct preliminary design and then adopting modern optimization design methods to implement multistage local optimization. Quasi-three dimensional(Q3D) design methods, which mainly refer to S2 flow surface direct problem calculation, adopt the S2 flow surface direct problem calculation program of Harbin Institute of Technology. Multistage local optimization adopts the software of Numeca/Design3D, which jointly adopts genetic algorithm and artificial neural network. The major principle of the methodology is that the successive design evaluation is performed by using an artificial neural network instead of a flow solver and the genetic algorithms may be used in an efficient way. Flow computation applies three-dimensional viscosity Navier Stokes(N-S) equation solver. Such optimization process has three features: (i) local optimization based on aerodynamic performance of every cascade; (ii) several times of optimizations being performed to every cascade; and (iii) alternate use of coarse grid and fine grid. Such process was applied to optimize a three-stage axial turbine. During the optimization, blade shape and meridional channel were respectively optimized. Through optimization, the total efficiency increased 1.3% and total power increased 2.4% while total flow rate only slightly changed. Therefore, the total performance was improved and the design objective was achieved. The preliminary design makes use of quasi-three dimensional(Q3D) design methods to achieve most reasonable parameter distribution so as to preliminarily enhance total performance. Then total performance will be further improved by adopting multistage local optimization design. Thus the design objective will be successfully achieved without huge expenditure of manpower and calculation time. Therefore, such optimization design process may be efficiently applied to the aerodynamic design optimization of multistage axial turbine.

• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.127-137
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• 2012

Recently, as modern Internet uses mashups, Web 3.0, JavaScript/AJAX widely, the rate at which new vulnerabilities are being discovered is increasing rapidly. It can subsequently introduce big security threats. In order to efficiently mitigate these web application vulnerabilities and security threats, it is needed to rank vulnerabilities based on severity and consider the severe vulnerabilities during a specific phase of software development lifecycle (SDLC) for web applications. In this paper, we have first verified whether the risk rating methodology of OWASP Top 10 vulnerabilities is a reasonable one or not by analyzing the vulnerability data of web applications in the US National Vulnerability Database (NVD). Then, by inspecting the vulnerability information of web applications based on OWASP Top-10 2010 list and CWE (Common Weakness Enumeration) directory, we have mapped the web-related entries of CWE onto the entries of OWASP Top-10 2010 and prioritized them. We have also presented which phase of SDLC is associated with each vulnerability entry. Using this approach, we can prevent or mitigate web application vulnerabilities and security threats efficiently.

• Journal of the Society of Disaster Information
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• v.17 no.1
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• pp.53-59
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• 2021

Purpose & Method: The purpose of this study is the theoretical study on the durability standard of ground structures monitoring sensors. A survey on the durability criteria for construction monitoring sensors of domestic construction companies and the income tax implementation regulations, the standard years of contents such as buildings and the standards of the Public Procurement Service for construction monitoring and construction machinery were analyzed. Result: The durability criterion such as the inclination meter and the strain gauge, which are purchased from the Public Procurement Service prior to installation on the ground structure, is 8 to 10 years. Conclusion: The actual durability analysis by comparing the reliability of various monitoring sensors installed in dams at home and abroad, As a result of comprehensive study on the loss and damage rate of the maintenance monitoring sensor installed in the tunnel, the proper durability period of the built-in type monitoring sensor such as domestic pore pressure meter and earth pressure meter installed in the structure or the ground is 5 to 8 years it seems reasonable.

• Journal of Bone Metabolism
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• v.25 no.4
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• pp.251-266
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• 2018

Background: The causal networks among genes that are commonly expressed in osteoblasts and during bone metastasis (BM) of breast cancer (BC) are not well understood. Here, we developed a machine learning method to obtain a plausible causal network of genes that are commonly expressed during BM and in osteoblasts in BC. Methods: We selected BC genes that are commonly expressed during BM and in osteoblasts from the Gene Expression Omnibus database. Bayesian Network Inference with Java Objects (Banjo) was used to obtain the Bayesian network. Genes registered as BC related genes were included as candidate genes in the implementation of Banjo. Next, we obtained the Bayesian structure and assessed the prediction rate for BM, conditional independence among nodes, and causality among nodes. Furthermore, we reported the maximum relative risks (RRs) of combined gene expression of the genes in the model. Results: We mechanistically identified 33 significantly related and plausibly involved genes in the development of BC BM. Further model evaluations showed that 16 genes were enough for a model to be statistically significant in terms of maximum likelihood of the causal Bayesian networks (CBNs) and for correct prediction of BM of BC. Maximum RRs of combined gene expression patterns showed that the expression levels of UBIAD1, HEBP1, BTNL8, TSPO, PSAT1, and ZFP36L2 significantly affected development of BM from BC. Conclusions: The CBN structure can be used as a reasonable inference network for accurately predicting BM in BC.

• Korean Medical Education Review
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• v.21 no.1
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• pp.41-50
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• 2019

The aim of this study is to analyze the current status and performance evaluation systems of faculty in Korean medical colleges and professional graduate medical schools (called medical schools). We developed a research tool based on previous studies and distributed it to 40 medical schools from July to October 2017. The response rate was 100%. We calculated the number of faculty members and analyzed the faculty evaluation systems and awareness according to national and private medical schools. As of 2017, the number of medical faculty in Korea was 11,111 (4,973 faculty were employed by their alma mater, which is 44.76% of the total), with non-medical doctor faculty accounting for 754 of the total. The medical schools reflect research achievements as most important for re-appointment and screening to promote faculty, and the area of education is secondary excepting clinical faculty of private medical schools. However, important issues in the faculty evaluation deal with the relevance of research achievement and the need for qualitative assessment. Some medical schools revised or have been revising the faculty evaluation system in areas such as minimum standards of education for promotion and separation of promotion and tenure review. Opening non-tenure track lines for faculty show positive effects such as increasing the number of positions for hire and easing the financial burdens of medical schools. Downfalls include inconsistencies between the responsibilities and actual practices of tenure not being available and the instability of faculty's status. In conclusion, medical schools need to prepare a faculty evaluation system that fits the position of faculty members and attempt to establish a reasonable compensation system.

• Journal of Korean Foot and Ankle Society
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• v.22 no.3
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• pp.111-115
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• 2018

Purpose: Ingrown toenails are a common disease in the adolescent period and the treatments could be more conservative for this early stage of the disease. This study is a case series on the results of a gutter splint for an adolescent ingrown toe nail as a simple, comfortable treatment method. Materials and Methods: From 2011 to 2018, 22 patients (mean age, 12.2 years; range, 8~15 years) with ingrown toenails were treated with a gutter splint. There were 16 boys and 6 girls with 7 patients on both great toes, and additional 4 both corners of a nail, giving a total of 33 splints. Flat, plastic straws and glue or suture were used to protect the nail corners under local anesthesia. The medical records were reviewed retrospectively and phone calls were made to obtain the long-term results. Results: Fifteen splints were fixed with a suture and the other 18 splints were fixed with glue. There were 9 cases of recurrence out of 33 gutter splints, 8 out of 15 sutured splints and 1 out of 18 glued splints (p=0.010). There was no gender (p=0.383) or age (p=0.305) difference in the number of recurrences. Conclusion: For growing people, ingrown nails can be cured easily by conservative treatment for a transiently shortened or broken toenail. The glued gutter splint had a reasonable success rate as a first line treatment.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.79-92
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• 2019

Titanium hydride potassium perchlorate (THPP) is one of the commonly utilized pyrotechnic materials in aerospace industries. The current study elucidates the effects of hygrothermal aging on the combustion of THPP experimentally. First, applying the Differential Scanning Calorimetry (DSC) and isocoversional method, both the delay of reaction start and decrease in maximum reaction rate were observed. The kinetics parameters tended to fluctuate depending the thermal reaction or intermediate product formation of THPP. Also, the oxidants decomposition and fuel oxidation phenomenon were discovered by X-ray photoelectron spectroscopy (XPS). The experimental heat from DSC data were verified as reasonable by comparing with the theoretical heat obtained utilizing both THPP formulation from XPS and NASA Chemical Equilibrium with Applications (CEA). Both data had identical variation trend, which expecially had the highest heat value at 10 weeks aged sample.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.2
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• pp.25-39
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• 2019

The water pollution Accident in the South Han River is increasing due to increase of pollutants inflow from small streams from rural areas and reduced flow rate. This study predicted the change of water quality in the main stream of the South Han River due to climate change through the linkage of watershed and water quality models. Also, This study analyzed the effect of water quality improvement on Seomgang and the South Han River by securing the flow during the dry season. According to the scenarios for securing the river flow during drought season, the river flow in the Seomgang is increased up to 2.19 times, and the water quality during the drought season was improved up to $BOD_5$ 20.5%, T-N 40.8%, T-P 53.4%. Also, the water quality of the main stream of the South Han River improved to 5.22% of $BOD_5$, 5.42% of T-N and 7.69% of T-P as the river flow was secured from the Seomgang. The result of this study confirms that securing the baseflow in the Seomgang according to the scenarios for securing the river flow during the dry season has a positive effect on the improvement of the water quality of the rivers in the main river of the Seomgang and South Han River. The results of this study will contribute to the establishment of reasonable management to improve the water quality of the main stream of the Seomgang and South Han River.

• Membrane and Water Treatment
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• v.10 no.1
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• pp.13-17
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• 2019

This study was conducted to analyse the application of pollutant build-up model on various urban landuses and to characterize pollutant build-up on urban areas as a source of stormwater runoff pollution. The monitored data from impervious surfaces in urban areas such as commercial (8 sites), industrial (10 sites), road (8 sites), residential (10 sites), recreational (5 sites) from 2008 to 2016 were used for the analysis of pollutant build-up model. Based on the results, the average runoff coefficients vary from 0.35 to 0.61. In all landuses except recreational landuse, the runoff coefficient is 0.5 or more, which is the highest in the commercial area. Commercial landuse where pollutants occur at the highest EMC in all landuse, and it is considered that NPS management is necessary compared with other landuses. The maximum build-up load for organic matter (BOD) was highest in the commercial area ($4.59g/m^2$), and for particular matter (TSS) in the road area ($5.90g/m^2$) while for nutrient (TN and TP) in the residential area ($0.40g/m^2$, $0.14g/m^2$). The rate constants ranged from 0.1 to 1.3 1/day depending on landuse and pollutant parameters, which means that pollutant accumulation occurs between 1 and 10 days during dry day. It is clear that these build-up curves can generally be classified based on landuse. Antecedent dry day (ADD) is a suitable and reasonable variable for developing pollutant build-up functions. The pollutant build-up curves for different landuse shows that these build-up curves can be generally categorized based on landuse.

• Journal of Information Technology Services
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• v.17 no.4
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• pp.101-117
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• 2018

Companies are responding appropriately to the rapidly changing business environment and striving to lead those changes. As part of that, we are meeting our strategic goals through IT projects, which increase the number of simultaneous projects and the importance of project portfolio management for successful project execution. It also strives for efficient deployment of human resources that have the greatest impact on project portfolio management. In the early stages of project portfolio management, it is very important to establish a reasonable manpower plan and allocate performance personnel. This problem is a problem that can not be solved by linear programming because it is calculated through the standard deviation of the input ratio of professional manpower considering the uniformity of load allocated to the input development manpower and the importance of each project. In this study, genetic algorithm, one of the heuristic methods, was applied to solve this problem. As the objective function, we used the proper input ratio of projects, the input rate of specialist manpower for important projects, and the equal load of workload by manpower. Constraints were not able to input duplicate manpower, Was used as a condition. We also developed a program for efficient application of genetic algorithms and confirmed the execution results. In addition, the parameters of the genetic algorithm were variously changed and repeated test results were selected through the independent sample t test to select optimal parameters, and the improvement effect of about 31.2% was confirmed.