• Communications of the Korean Mathematical Society
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• v.38 no.3
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• pp.663-677
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• 2023

The purpose of this paper is to introduce a new class of rings containing the class of SFT-rings and contained in the class of rings with Noetherian prime spectrum. Let A be a commutative ring with unit and I be an ideal of A. We say that I is SFT if there exist an integer k ≥ 1 and a finitely generated ideal F ⊆ I of A such that x^k ∈ F for every x ∈ I. The ring A is said to be nonnil-SFT, if each nonnil-ideal (i.e., not contained in the nilradical of A) is SFT. We investigate the nonnil-SFT variant of some well known theorems on SFT-rings. Also we study the transfer of this property to Nagata's idealization and the amalgamation algebra along an ideal. Many examples are given. In fact, using the amalgamation construction, we give an infinite family of nonnil-SFT rings which are not SFT.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.5
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• pp.215-226
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• 2018

In this paper, to estimate the dynamic behavior of a submerged floating tunnel(SFT) by underwater explosion(UE), the SFT is modeled and analyzed by the explicit structural analysis package LS-DYNA. The section of SFT near to explosion point is modeled to shell and solid elements using elasto-plasticity material model for concrete tubular section and steel lining. And the other parts of the SFT are modeled to elastic beam elements. Also, mooring lines are modeled as tension-only cable elements. Total mass of SFT is including an added mass by hydrodynamic effect. The buoyancy on the SFT is considered in its initial condition using a dynamic relaxation method. The accuracy and the feasibility of the analysis model aree verified by the results of series of free field analysis for UE. And buoyancy ratio(B/W) of SFT, the distance between SFT and an explosion point and the arrangement of mooring line aree considered as main parameters of the explosion analysis. As results of the explosion analysis, the dynamic responses such as the dent deformation by the shock pressure are responded less as more distance between SFT and an explosion point. However, the mooring angle of the diagonal mooring system can not affect the responses such as the horizontal displacement of SFT by the shock pressure.

• Structural Engineering and Mechanics
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• v.88 no.4
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• pp.323-334
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• 2023

The submerged floating tunnel (SFT) infrastructure has been regarded as an emerging technology that efficiently and safely connects land and islands. The SFT route problem is an essential part of the SFT planning and design phase, with significant impacts on the surrounding environment. This study aims to develop an optimization model considering transportation and structure factors. The SFT routing problem was optimized based on two objective functions, i.e., minimizing total travel time and cumulative strains, using NSGA-II. The proposed model was applied to the section from Mokpo to Jeju Island using road network and wave observation data. As a result of the proposed model, a Pareto optimum curve was obtained, showing a negative correlation between the total travel time and cumulative strain. Based on the inflection points on the Pareto optimum curve, four optimal SFT routes were selected and compared to identify the pros and cons. The travel time savings of the four selected alternatives were estimated to range from 9.9% to 10.5% compared to the non-implemented scenario. In terms of demand, there was a substantial shift in the number of travel and freight trips from airways to railways and roadways. Cumulative strain, calculated based on SFT distance, support structure, and wave energy, was found to be low when the route passed through small islands. The proposed model helps decision-making in the planning and design phases of SFT projects, ultimately contributing to the progress of a safe, efficient, and sustainable SFT infrastructure.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.3
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• pp.262-266
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• 2009

Solitary fibrous tumor (SFT) is a neoplasm that arises most commonly in pleura. Although SFT occasionally occurs in extrapleural locations, the incidence in the oral cavity is rare. SFT is benign in almost cases and surgical excision is the effective treatment. SFT occurred in the left cheek of a 60-year-old man presented with a painless submucosal mass. The tumor was surgically removed. Immunohistochemical study showed that tumoral cells were negative for SMA, S-100, but positive for Bcl-2, CD34. SFT is easily over-diagnosed if strict criteria are not carefully applied, and strict diagnostic criteria are necessary to avoid confusion of SFT with more aggressive lesions.

• Ocean Systems Engineering
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• v.7 no.1
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• pp.1-19
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• 2017

This paper presents the numerical simulation results for the dynamic responses of two types of submerged floating tunnels (SFT) under wave and/or seismic excitations. Time domain simulations are conducted by the commercial program OrcaFlex (OF) and in-house CHARM3D program (CP). The dynamic performances of a short/rigid/free-end SFT section with vertical and inclined mooring lines are evaluated. The SFT numerical models were validated against Oh et al.'s (2013) model test results under regular wave conditions. Then the numerical models were further applied to the cases of irregular waves or seismic motions. The main results presented are SFT surge/heave motions and mooring tensions. The general trends and magnitudes obtained by the two different software packages reasonably agree to each other along with experimental results. When seabed seismic motions are applied to the SFT system, the dynamic responses of SFTs are small but dynamic mooring tension can significantly be amplified. In particular, horizontal earthquakes greatly increase the dynamic tension of the inclined mooring system, while vertical earthquakes cause similar effect on vertical mooring system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.136-144
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• 2017

This study analyzed the influence of Qigong exercise intervention upon a change in glucose, blood lipid, and SFT(senior fitness test) of elderly women and to closely examine the efficacy of a Qigong exercise intervention to promote the health of older women. As research subjects, 24 elderly women aged over 80 were divided into Qigong group(n=12) and control group(n=12), respectively, and the program was carried out for 60 minutes per a day, five times per week for 24 weeks. Data were analyzed using SPSS WIN 20.0, repeated measures ANOVA. The Qigong group had a significantly lower glucose level than the control group. Second, the blood lipid and neutral fat(TG) was reduced significantly in the Qigong group than the control group. The total cholesterol(TC), high-density lipoprotein(HDL-C), and low-density lipoprotein(LDL-C) did not show a significant difference. Third, as for SFT, the leg strength, leg flexibility, and total body endurance were significantly higher in the Qigong group than in the control group. Therefore, Qigong has an influence on the reduction in glucose and neutral fat(TG) and upon the improvement in SFT(leg strength, leg flexibility, and total body endurance) of elderly women, and may show effectiveness as an exercise prescription program for older women.

• Journal of Korean Neurosurgical Society
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• v.46 no.1
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• pp.77-80
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• 2009

Orbital solitary fibrous tumor (SFT) is a rare tumor originating from the mesenchyme. We describe the clinical presentations, radiological and operative findings, and pathological features of a patient with orbital SFT. The patient was a 46-year-old female who presented with progressive proptosis advanced for 20 months. On ophthalmological examination, no visual impairment was detected, but left eye was found to be obviously protruded on exophthalmometry. Orbital magnetic resonance imaging showed a 2.5 ${\times}$ 2 ${\times}$ 2 cm, intensely enhanced mass in the left orbit, which compressed the eyeball forward and the optic nerve downward. The patient underwent frontal craniotomy with superior orbitotomy and gross total resection was performed for the tumor. The histopathological diagnosis including immunohistochemistry was a SFT. After the surgery, proptosis was markedly relieved without visual impairment. Although orbital SFT is extremely rare, it should be considered in the differential diagnosis of orbital tumors. Clinical presentations such as painless proptosis and CD34 immunoreactivity play a significant role in differentiating orbital SFT from other spindle-cell neoplasms of the orbit.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.1
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• pp.1-5
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• 2000

Studies on the genetic and environmental effects on M.longissimus thoracis area (MLTA), fat thickness (SFT), rib thickness (RT) and marbling score (MS) were conducted on 21,086 steers and 7,151 heifers of Japanese Brown breed. All carcass traits were affected significantly (p<0.01) by sire, sex and initial year effects. Both of the MLTA and MS of steers were greater than heifers. Their differences were $1.4cm^2$ for MLTA and 0.05 for MS, respectively. Cattle started for fattening in winter tend to have higher of MLTA and MS and thicker of SFT and RT than those in other seasons. MLTA increase from 1987 to 1989 (about $1.9cm^2$) and decrease until 1994 (about $2.4cm^2$) and then increase again up to 1995 (about $1.5cm^2$). MS were nearly equal from 1987 to 1991 (about "1") and then decrease up to 1995 (about "1"). Heritability estimates of MLTA, RT, SFT and MS were ranged from 0.22 to 0.36. Genetic and phenotypic correlations of MLTA, RT, SFT and MS were positive and ranged from 0.05 to 0.62 and from 0.03 to 0.32 except SFT with MLTA was negative (-0.14 and -0.03).

• Journal of Korean Neurosurgical Society
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• v.54 no.3
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• pp.246-249
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• 2013

A solitary fibrous tumor (SFT) is a rare neoplasm originated from the pleura, but they can occur in a variety of extrathoracic regions. Although many cases of primary SFT have been reported, there are extremely rare repots to date of a malignant SFT in the spine or skull. A 54-year-woman visited our hospital due to low back pain and both leg radiating pain. Several imaging studies including magnetic resonance imaging and computed tomography revealed expansive enhanced lesions in the occipital bone, T8, S1-2, and ilium, with neural tissue compression. We performed surgical resection of the tumor in each site, and postoperative radiosurgery and chemotherapy were performed. However, after six months, tumors were recurred and metastasized in multiple regions including whole spine and lung. The authors report here the first case of patient with malignant SFT of tandem lesions in the various bony structures, including skull, thoracic spine, and sacral spine, with a rapid recurrence and metastasis. Although malignant SFT is extremely rare, it should be considered in the differential diagnosis and carful follow-up is needed.

• Journal of Clinical Otolaryngology Head and Neck Surgery
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• v.29 no.2
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• pp.254-258
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• 2018

The solitary fibrous tumor (SFT) is a mesenchymal neoplasm that is described as spindle-shaped tumor cells on a collagenous background originating from pleural tissues. Recently, extrapleural SFT has been reported in nearly all sites, including the sublingual gland, parotid gland, nasal cavity and paranasal sinuses. Complete surgical excision is primary treatment for SFT, but diagnosing SFT is not often made until immunohistochemical evaluation after surgical resection. We report that the patient, 45-year-old male, was considered as a case of inflammation polyp arising from left nasal cavity with initial biopsy, however, it has turned out to be SFT after surgical treatment.