• Archives of Craniofacial Surgery
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• v.10 no.2
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• pp.81-85
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• 2009

Purpose: The inferior orbital wall is the most vulnerable to injury and inadequate reconstruction of inferior orbital fracture result in postoperative complications include enophthalmos, ocular dystopia and diplopia. Although the anatomical reconstruction of the inferior orbital wall is necessary to prevent these complications, the complexity of inferior orbital wall makes it difficult. We fabricated and remodeled the titanium micro-mesh plate for the anatomical reconstruction of inferior orbital wall. Methods: Twenty-nine patients with inferior orbital wall blow-out fracture were operated and twelve of them presented large extensive fracture. We intraoperatively fabricated and remodeled the Titanium-micro mesh to angulated lazy S shape similar to contralateral uninjured orbit. The preoperative and postoperative facial CT scan verified the 3-dimensional and anatomical reconstruction of the fractures. The mean follow-up was 19.7 months and postoperative complications was evaluated. Results: All cases showed the exact anatomical reconstruction, but there were minor complications in two cases. one patient had postoperative diplopia until 3months after surgery and the other patient had persistent enophthalmos (2 mm), but no further surgical correction was required. Conclusion: The comprehensive understanding of orbital convexity is the most important factor for anatomical reconstruction of inferior orbital fracture. We could prevent postoperative complications after inferior orbital wall reconstruction by intraoperative fabrication and anatomical remodeling of Titanium micro-mesh.

• Archives of Plastic Surgery
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• v.38 no.1
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• pp.35-42
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• 2011

Purpose: Blow-out fractures can be reduced using various methods. The orbital reconstruction technique using a balloon under endoscopic control has advantages over other methods. However, this method has some problems too, such as postoperative follow-up, management of the balloon catheter, and reduction of the posterior orbital floor. Thus, we developed a simple, effective method for orbital floor reduction that involves molding and shaping the antral balloon catheter. Methods: A 0, 30, or $70^{\circ}$, 4-mm endoscope was placed though a two-point, 5-mm maxillary antrostomy. The balloon catheter is placed directly at the orbital apex to reconstruct the anterior shelf (spherical shape), while it is turned in a U-shape towards the anterior maxilla for the posterior shelf (elliptical shape). Orbital floor defects, compound or comminuted fractures are reconstructed with alloplastic materials through an open lid incision under the endoscopic control. Results: This technique was applied to ten patients with orbital floor fractures: five anterior shelf and five posterior shelf fracture, respectively. Four of the patients had zygomatico-orbital fractures, while the rest had isolated orbital floor fractures. Two patients were given porous polyethylene implants Synpor$^{(R)}$) and three underwent reconstruction with a resorbable mesh plate. No complication associated with this technique was identified. Conclusion: The freestyle placement and selection of a urinary balloon catheter under endoscopic control and the preoperative estimation of the volume enhanced the stabilization of the orbital contour. This method improves the adaptation of the orbital floor without the risk of injuring the surrounding orbital contents, dissecting blindly, or using sharp traction. One drawback of this method is the patient's discomfort from the catheter during treatment.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.126-133
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• 2007

An experimental apparatus has been designed and prepared in order to measure a pressure loss coefficient of hydropneumatic components, which is an important parameter in a hydropneumatic system Blow-down system has been adopted for the experimental apparatu to meet the high flow energy requirement as well as the apparatus safety. Especially, pressure loss coefficient measurements of pyrostarter filters have been performed and the pressure loss coefficient, K of CQSF has been experimentally acquired. Then it is shown that the turbine inlet pressure $p_2$, which is predicted from the measured K, is in accord with the results of combustion tests. Moreover, the relation between K and combustion pressure $p_0$ has been presented and it is disclosed that the relation accords well with the results of combustion tests. It is anticipated that K of a filter could play a role in PS size reduction by rising up the combustion pressure resulting in increasing the burning rate of solid propellant.

• Archives of Plastic Surgery
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• v.36 no.4
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• pp.428-431
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• 2009

Purpose: Blow out fracture resulting from facial trauma is of high frequency among facial bone fractures, and can cause severe complications. So, proper management and close observation after operation are needed. So far, Computed tomography has been the best choice in the evalution following orbit wall reconstruction. However, cost - effectiveness, accessibility to patients and hazard of radiation exposure of computed tomography require supplementary measure for the evaluation following orbit wall reconstruction. This study was performed to describe the effectiveness of ultrasonography in the evalution following orbit wall reconstruction. Methods: A retrospective study was performed on 40 patients who underwent orbit wall reconstruction from June, 2008 to July, 2008. The patients' ages ranged from 13 to 65 years (mean 27.5 years), and this group was compsoed of 27 male and 13 female patients. The follow up period ranged from 2 weeks to 28 weeks (mean 11weeks). Preoperatively, all fractures were diagnosed using computed tomography. Ultrasonography for all cases, and computed tomography for 2 cases were performed for evaluation following orbit wall reconstruction. Results: Reduction of herniated orbital soft tissue and orbit implant was identified by using ultrasonography in 38 cases out of 40 cases. In other cases which we could not identify the orbit implant, computed tomography was performed. Con clusion: Compared to computed tomography, ultrasonography is simple, inexpensive and convenient method. Ultrasonography can be used as supplementary measure to computed tomography in the evaluation following orbit wall reconstruction for elective patients.

• Journal of Korea Trade
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• v.27 no.5
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• pp.137-152
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• 2023

Purpose - Although many existing studies on the US-China hegemonic conflict and decoupling have been published, most of them are qualitative and use descriptive analysis methods. Papers that quantitatively analyzed decoupling mainly estimate the effect of a tariff increase. However, this paper quantitatively analyzed the ripple effect by focusing on decoupling technology spillover between the United States and China. And, for the first time, it was suggested that the blocking of technology spillover could give a fatal blow to the East Asian economy as well as China. Design/methodology - The United States is pursuing decoupling with China, primarily in goods trade and blocking technology transfer. This paper sets up various scenarios and uses three computational general equilibrium (CGE) models to analyze the overall ripple effects of decoupling. A paper using the three CGE models for decoupling ripple effect analysis has not yet been published. Findings - Decoupling will hit the economies of regions with close economic ties to China more than others. According to simulation results of this study, the Chinese economy may suffer severe damage that is difficult to recover from, and the economies of Asian countries are predicted to deteriorate to the point of being choked. Originality/value - Existing papers that assessed the effect of decoupling mostly focus on estimating the effect itself through tariff hikes. This paper is meaningful in that it comprehensively analyzed decoupling by adding the effect of technology spillover blockade. In addition, another meaning can be found in that it quantified for the first time that it will deal a huge blow to the extent of choking the East Asian economy as well as China.

• Journal of applied mathematics & informatics
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• v.32 no.5_6
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• pp.721-736
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• 2014

We consider the equation ${\Delta}_mu=p(x)u^{\alpha}+q(x)u^{\beta}$ on $R^N(N{\geq}2)$, where p, q are nonnegative continuous functions and 0 < ${\alpha}{\leq}{\beta}$. Under several hypotheses on p(x) and q(x), we obtain existence and nonexistence of blow-up solutions both for the superlinear and sublinear cases. Existence and nonexistence of entire bounded solutions are established as well.

• Journal of applied mathematics & informatics
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• v.28 no.1_2
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• pp.1-11
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• 2010

The conditional covering problem is an important variation of well studied set covering problem. In the set covering problem, the problem is to find a minimum cardinality vertex set which will cover all the given demand points. The conditional covering problem asks to find a minimum cardinality vertex set that will cover not only the given demand points but also one another. This problem is NP-complete for general graphs. In this paper, we present an efficient algorithm to solve the conditional covering problem on interval graphs with n vertices which runs in O(n)time.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.559-561
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• 2011

멀티코어 환경에서는 공유 데이터에 대한 동기화로 인한 병목 현상이 중요한 문제점 중의 하나이다. 그리고 동적 메모리 할당자는 대량의 메모리를 할당 및 해제하는 프로그램에서 공유 데이터에 대한 동기화 문제로 성능 저하를 유발시키고 있다. 이를 해결하기 위해 다양한 lock-free 메모리 할당 기법들이 소개되었지만 false sharing과 heap blow-up과 같은 여러 가지 문제점들을 가지고 있다. 이에 본 논문에서는 새로운 연속할당 기법을 제안하고, 이를 이용하여 동일 블록 내의 오브젝트 할당/해제에 따른 동기화 문제를 해결함으로써 효과적인 lock-free 메모리 할당 기법을 제안하였다. 그리고 제안 기법을 구현하여 기존의 메모리 할당 기법들과 실험을 통하여 검증하였으며, 대량의 메모리를 사용하는 멀티 스레드 환경에서 특히 좋은 성능을 보이는 것을 확인하였다.

• Journal of the Korean Mathematical Society
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• v.47 no.6
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• pp.1317-1328
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• 2010

In this paper, we study the properties of positive solutions for the reaction-diffusion equation $u_t$ = $\Delta_u+{\int}_\Omega u^pdx-ku^q$ in $\Omega\times(0,T)$ with nonlocal nonlinear boundary condition u (x, t) = ${\int}_{\Omega}f(x,y)u^l(y,t)dy$ $\partial\Omega\times(0,T)$ and nonnegative initial data $u_0$ (x), where p, q, k, l > 0. Some conditions for the existence and nonexistence of global positive solutions are given.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.6
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• pp.677-680
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• 2000

Orbital injuries are common with facial trauma. Direct injuries to the globe are not rare but it can result in complications such as chemosis, subconjunctival hemorrhage and hyphema. Periorbital trauma or injuries to the extraocular muscles and blow-out fracture may result in lid edema, ecchymosis & ptosis and diplopia or limitation of ocular motion respectively. Indirect injuries to the optic nerve come up without any injuries but its complication is irreversible and severe such as loss of vision. The aim of this study is to review the literature on blindness or ptosis following facial trauma and present the cases of blindness after facial trauma and ptosis after mandibular fracture without specific clinical findings.