• Transactions of the Korean Society of Mechanical Engineers
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• 제16권10호
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• pp.1877-1889
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• 1992

Upsetting is performed in open-die press forging to deform metal in all directions in order to enhance soundness of a product and reduce directionality of properties caused by casting. It is necessary to ensure sufficient forging ratio for subsequent cogging operations and consolidate the void along the centerline. To obtain these benefits, the upper die shape (dome and dished shape) is considered as an upsetting parameter. Thermo-viscoplastic finite element analysis has been carried out so as to understand the influence of upper die shape on the effective strain, hydrostatic stress and temperature in the upset-forged ingots without internal defects. The analysis is focused on the investigation into internal void closure in ingots with pipe holes and circular voids. The computational results have shown that the volume fraction of the void is independent of the circular void size and the closure of internal voids is much more influenced by the effective strain than the hydrostatic stress around the void. It is finally suggested that the height reduction must be over 35% for consolidation of internal voids.

• Information Systems Review
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• 제10권1호
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• pp.21-45
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• 2008

Over the years a lot of organizations or enterprises are spending the majority of their IT budgets on IT resources procurement and maintenance. IT resources are typically duplicated in each Region, Division, and/or Business Unit. The biggest sources of cost savings come directly from the reduction in maintenance cost and the elimination of duplicated resources. Global corporations are investing heavily in shared services implementations in order to stay competitive in an industry environment. A number of financial services firms have turned to IT shared services to reduce the level of IT asset and infrastructure redundancies. Recently, Korean financial services industry is moving to diversification(bank, securities, insurance, etc.) and consolidation(M&A, strategic alliance, etc.), and wants the elimination of duplicated IT resources. This research is intended to find out and demonstrate the factors having a significant effect on adoption of IT shared services center in finance services industry.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.336-345
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• 2010

GS E&C was awarded the contract for the construction of Hanoi - Hai Phong Expressway Package EX-7 from Station Km 72+000 to Station Km 81+300 in December 2008. This project is the $7^{th}$ contract package of the 105.5 km long expressway near Hai Phong city, which includes a FCM-styled bridge along with high embankments over soft ground. For these high embankments, there is a need to treat the soft soil for improving the overall stability during construction and for reducing the post-construction settlement of the expressway. The Designer of this project had adopted four (4) different types of ground improvement techniques to treat the soft ground, including the prefabricated vertical drains (PVD), sand drains (SD), pack drains (PD, or sometimes called packed sand drains), and sand compaction piles (SCP). The main focus of soft soil treatment should be paid attention to the residual settlement after construction. In current design, however, it appeared that the secondary compression (or creep) of the improved soil layer and the consolidation settlement of the lower untreated compressible soil layer have been neglected in the estimation of the post-construction settlement. These uncalculated residual settlements may not only unsatisfy the design criteria but also raise serious problems during service period of this expressway. In this paper, the subsoil condition and current design were reviewed focusing on the employed soft soil treatment method and expected residual settlement.

• Structural Engineering and Mechanics
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• 제52권6호
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• pp.1069-1084
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• 2014

The long-term performance of plates resting on viscoelastic foundations is a major concern in the analysis of soil-structure interaction. As a powerful mathematical tool, fractional calculus may address these plate-on-foundation problems. In this paper, a fractionalized Zener model is proposed to study the time-dependent behavior of a uniformly loaded rectangular thin foundation plate. By use of the viscoelastic-elastic correspondence principle and the Laplace transforms, the analytical solutions were obtained in terms of the Mittag-Leffler function. Through the analysis of a numerical example, the calculated plate deflection, bending moment and foundation reaction were compared to those from ideal elastic and standard viscoelastic models. It is found that the upper and lower bound solutions of the plate response estimated by the proposed model can be determined using the elastic model. Based on a parametric study, the impacts of model parameters on the long-term performance of a foundation plate were systematically investigated. The results show that the two spring stiffnesses govern the upper and lower bound solutions of the plate response. By varying the values of the fractional differential order and the coefficient of viscosity, the time-dependent behavior of a foundation plate can be accurately captured. The fractional differential order seems to be dependent on the mechanical properties of the ground soil. A sandy foundation will have a small fractional differential order while in order to simulate the creeping of clay foundation, a larger fractional differential order value is needed. The fractionalized Zener model is capable of accounting for the primary and secondary consolidation processes of the foundation soil and can be used to predict the plate performance over many decades of time.

• Journal of Korean Medical classics
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• 제12권1호
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• pp.113-138
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• 1999

Distension of hydrops is the pathosis that the hydration is retented in abdomen and that is caused by disturbance of hydrometabolism. Most of hydrops belongs to Consolidation. In part of OhRyungJinAek-Byeul of Youngchu"靈樞 五癃津液別", the general explanation of hydrops is briefed. But there was nothing about pathogenesis, pathology, symptoms and the method of treatment. The part SuChang of Youngchu "靈樞 水脹" divided it by Superficial-swelling, Hidden-swelling, Ovarian-hydrops, Stony-uterin-mass and explained it to cure by Category of pathology. So, the books JeByeongWonHuRon"諸病源候論" ChonGeumYoBang"千金要方", WoiDaeBiYo"外臺秘要", TaePyeungSeongHyeBang"太平聖惠方", BoJeBang"普濟方", EuiHakGangMok"醫學綱目", DongEuiBoGam"東醫寶鑑" etc. published later, show the method of treatments and medications with quotation the original text of this part. And it is convinced that more profound research of this part is inevitable to understand the correct meaning of hydrops that explained by many of ancient medical scholars, and to apply it to clinical medicine. There is an explanation on Distension hydrops in the prologue of this part. And t six kinds of disease in this part is simila to edema, so it is called SuChang"水脹", pathology of Edema. Superficial-swellin Hidden-Swelling is reported in the fir chapter, differential diagnosis of Ovarian-hydrops, Stony-uterin-mass is rep in the second chapter, and treatment Superficial swelling. Hidden Swelling reported in the third chapter. Briefly looking over that chapter, Distension of hydrops is recognized as stay of hydration at the abdomen as a result of disturbance of hydrometabolism and it says about symtoms, pathogenesis, pathology, differential diagnosis, treatment of Hydrops Superficial-swelling Hidden-swelling Ovarian-hydrops Stony-uterinmass. And it says about a few things that Superficial-swelling, Hidden-swelling could be differentiated by colors of skin and distension of abdomen, and Ovarian-hydrops, Stony-ulerin-mass could be differentiated that it occurs which sex and whether mensturation occurs or not, and treatment of Superficial-swelling, Hidden-swelling, Ovarian-hydrops.

• Korean Journal of Remote Sensing
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• 제30권2호
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• pp.161-172
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• 2014

Established in the lower reaches of the Nakdong river in Busan, the Noksan national industrial complex is one of the deepest soft ground areas in Korea. In case of the costal landfill having deep soft ground, there is a significant residual settlement over a long period of time. In this study, there was observed ground subsidence occurred in the Noksan national industrial complex from September 2002 to April 2007 by applying DInSAR and SBAS time series method using RADARSAT-1 and Envisat SAR datasets. As a result, it was calculated that ground subsidence developed at the velocity of about maximum 10 cm/yr and mean 6 cm/yr at the eastern center, west, western center and southern area contiguous on the coastline of the study area during the period from September 2002 to April 2007. In addition, the RADARSAT-1 average displacement map has been compared with the total displacement map observed by accurate magnetic probe extensometer during the period from 2001 to 2002. Since the time series displacement has shown a linear trend mostly, we consider that continuous monitoring should be needed until the ground subsidence of the study area has been stabilized.

• Tuberculosis and Respiratory Diseases
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• 제71권4호
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• pp.278-281
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• 2011

Allergic bronchopulmonary aspergillosis (ABPA) is a complex clinical entity resulting from an allergic immune response to Aspergillus species, and most often occurs in patients with asthma. ABPA is rarely observed in the absence of asthma, which is, in fact, the principal criterion for its diagnosis. Our patient was a 53-year-old woman with no history of bronchial asthma. She presented with a 1-month history of cough, mucopurulent nasal discharge, and localized pulmonary consolidation. Peripheral blood eosinophilia and elevated serum IgE were observed. Sinus radiography showed right maxillary sinusitis. Pathologic examination of bronchoscopic biopsy specimens revealed conglomerates of fungal hyphae. Pulmonary function and bronchial provocation tests were within normal ranges. The patient was successfully treated for 3 months with itraconazole and oral prednisolone. There has been no evidence of recurrence over a 7-month follow-up. ABPA coupled with sinusitis in a nonasthmatic patient is a very rare occurrence and warrants reporting.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제35권7호
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• pp.745-751
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• 2011

This study proposes finite element modeling of dislocation punching at cooling after consolidation in order to calculate the strength of particle-reinforced aluminum composites. The Taylor dislocation model combined with strain gradient plasticity around the reinforced particle is adopted to take into account the size-dependency of different volume fractions of the particle. The strain gradients were obtained from the equivalent plastic strain calculated during the cooling of the spherical unit cell, when the dislocation punching due to CTE (Coefficient of Thermal Expansion) mismatch is activated. The enhanced yield stress was observed by including the strain gradients, in an average sense, over the punched zone. The tensile strength of the SiCp/Al 356-T6 composite was predicted through the finite element analysis of an axisymmetric unit cell for various sizes and volume fractions of the particle. The predicted strengths were found to be in good agreement with the experimental data. Further, the particle-size dependency was clearly established.

• Clinical and Experimental Pediatrics
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• 제57권6호
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• pp.271-277
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• 2014

Purpose: A nationwide outbreak of Mycoplasma pneumoniae pneumonia (MP) refractory to macrolide antibiotics occurred in Korea during 2011. Steroid therapy has been reported to be both efficacious and well tolerated in pediatric patients with refractory MP. We compared clinical features and laboratory characteristics between children with refractory MP requiring steroid treatment and those with macrolide-responsive MP and evaluated the risk factors associated with refractory MP. Methods: We investigated 203 children who were admitted to our institution with MP from June to November 2011. Refractory MP was defined by persistent fever over $38.3^{\circ}C$ with progressive pulmonary consolidation or pleural effusion despite administration of appropriate macrolide antibiotics for 5 days or longer after admission. Steroid therapy was initiated on the fifth day after admission for refractory cases. Results: There were 26 patients with refractory MP requiring steroid therapy. The mean duration of steroid therapy was 5.4 days and most of the patients were afebrile within 24 hours after initiation of steroid therapy. The prevalence of refractory MP was higher in patients with pleural effusion, lobar pneumonia affecting more than 2 lobes, higher levels of serum lactate dehydrogenase, increased oxygen requirements, and longer duration of hospitalization. Atopic sensitization and history of asthma were also associated with refractory MP after adjusting for age and gender. Conclusion: Children with refractory MP had more severe pneumonia. Atopic sensitization and history of asthma may be risk factors for refractory MP requiring steroid therapy in Korean children.

• Journal of Technologic Dentistry
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• 제37권1호
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• pp.23-29
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• 2015

Purpose: The selective laser melting (SLM) process for dentistry, which is one of the additive manufacturing technologies (AM) allows for rapid production of a three-dimensional model with complex shape by directly melting metal powder. This process generates detailed items of a three-dimensional model shape through consolidation of a thin powder layer by utilizing both selective melting and laser beam simultaneously. In regard to SLM process, Fe-base powder, Ti-6AI-4V powder, AI-base powder, etc. have been researched. It is believed that the aforementioned technologies will be widely utilized in manufacturing metal parts using metal powder of raw material. This study chose Ni-Cr-Mo metal powder in order to manufacture metal powder materials that would be used in the selective laser melting for dentistry. Methods: This study manufactured metal powder using mechanical alloying technique (MA) among those metal powder manufacturing techniques. Moreover, this study aimed to utilize the metal powder manufactured after observing the characteristics of powder as preliminary data of Ni-Cr-Mo metal powder. This study could obtain the following conclusions within the experimental limitations. Results: As a result of mechanically alloying Ni-Cr-Mo powder over time, its mean particle size was $66.93{\mu}m$ $54.4{\mu}m$ and $45.39{\mu}m$ at 10h, 20h and 30h, respectively. The gtain form of metal powder by mechanical alloying technique was a sponge-like shape of irregular plate; however, the gtain form manufactured by high-pressure water aromization process had the following three types: globular type, chain type and oval type. Conclusion: This study found $37.65{\mu}m$ as the mean particle size of Ni-Cr-Mo metal powder, which was manufactured using water atomization technique under the following conditions: water atomization flux of 300 liter/min, hydraulic pressure of $400kgf/cm^2$ and injection angle of $45^{\circ}$. This study confirmed that the grain form of powder (solid particle form) would vary depending on the manufacturing process.