• Journal of KSNVE
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• v.8 no.4
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• pp.654-662
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• 1998

To predict the radiating noise from the vibrating surface, it is required to know the velocity distribution of vibrating surface exactly as possible as it can. Although it can be obtained by finite element method, their accuracy is limited by theuncertainty of preparing input data such as material propoerties, damping, excitation, and the actual boundary conditions. Experimental values are accurate but are seldom available as many asthe data points compared to FEM mesh. Therefore, hybrid method of experiment and finite element method, called modal expansion technique, is investigated for the preparatin of accurate element method at specified frequencies and for the verification of this scheme, related experiment is performed. In high frequency range above 2000 Hz, piezo-electric material is used as an actuator.

• Journal of the Korean Society of Safety
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• v.15 no.1
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• pp.19-27
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• 2000

This paper numerically deals with combined heat transfer in a enclosure with a block. The block affected by hot wall is located centrally in the enclosure with a radiating gray gas. The discrete ordinate method(DOM) was used for solving the radiative transfer equation. Both laminar and turbulent cases were investigated for various Rayleigh number and standard k-$\varepsilon$ model was adopted to turbulent case. The effects of optical thickness, wall emissivity and fluid-solid thermal conductivity ratio are investigated on the flow and temperature fields. This study shows that as the wall emissivity decreases, the temperature distribution gradually becomes uniform and the heat transfer is reduced in enclosure. It is expected that this study can help to design the energy system related to the combined heat transfer and operate it safely.

• The Korean Journal of Pain
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• v.18 no.2
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• pp.210-213
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• 2005

Acute viral meningitis and myositis are rare complications of varicella-zoster virus (VZV) reactivation. A 71-years-old immunocompetent man, who presented with lower back pain radiating to the left lower extremities, developed vesicles on the L5 dermatomal area. The next day, he had complained of aberrant vesicles on the trunk, face and scalp, with generalized myalgia, headache and dizziness. He was confirmed with VZV meningitis and myositis, as demonstrated by the presence of VZV DNA in the blood and cerebral spinal fluid using a polymerase chain reaction (PCR) amplification. PCR has been used in patients with a VZV infection associated neurological symptoms, and provides a useful tool for the early diagnosis of VZV-associated neurological disease. The patient was treated with bed rest, with intravenous acyclovir for the VZV infection, and intravenous Patient-controlled Analgesia for pain management and the prevention of postherpetic neuralgia. When he visited the outpatient department 3 months later, the skin lesion, leg pain, headache and myalgia had all improved, without sequelae. Here, this case is reported, with a discussion of the relevant literature on its diagnosis and management.

• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.355-358
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• 2013

Spinal extradural arachnoid cyst (SEAC) is a rare disease and uncommon cause of compressive myelopathy. The etiology remains still unclear. We experienced 2 cases of SEACs and reviewed the cases and previous literatures. A 59-year-old man complained of both leg radiating pain and paresthesia for 4 years. His MRI showed an extradural cyst from T12 to L3 and we performed cyst fenestration and repaired the dural defect with tailored laminectomy. Another 51-year-old female patient visited our clinical with left buttock pain and paresthesia for 3 years. A large extradural cyst was found at T1-L2 level on MRI and a communication between the cyst and subarachnoid space was illustrated by CT-myelography. We performed cyst fenestration with primary repair of dural defect. Both patients' symptoms gradually subsided and follow up images taken 1-2 months postoperatively showed nearly disappeared cysts. There has been no documented recurrence in these two cases so far. Tailored laminotomy with cyst fenestration can be a safe and effective alternative choice in treating SEACs compared to traditional complete resection of cyst wall with multi-level laminectomy.

• Journal of Korean Neurosurgical Society
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• v.29 no.4
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• pp.569-573
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• 2000

Spinal meningeal cyst of the sacrum is uncommon congenital lesion. We experienced two cases of sacral meningeal cyst, so called Tarlov's cyst, who presented with radiating pain. Magnetic resonance imaging is a highly effective way of locating and approximating the size of these entities, which generally appear as intraspinal masses of low intensity on T1-weighted and high intensity on T2-weighted images, similar to cerebrospinal fluid(CSF). We evaluated 2 patients who had Tarlov's cyst diagnosed with conventional MRI. The clinical features, radiological findings, gross appearances of the lesion at surgery, surgical technique, histopathological features of the cyst wall, and surgical outcome are described. We conclude that excellent result can be expected in the case of symptomatic Tarlov's cyst by surgical decompression.

• Journal of Korean Neurosurgical Society
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• v.59 no.6
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• pp.647-649
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• 2016

The device for intervertebral assisted motion (DIAM) is a dynamic implant that consists of a silicone bumper enveloped by a polyethylene terephthalate (PET) fiber sack. Silicone and PET were used because of their biological inertness, but repetitive motion of the spine can cause wear on the implant nonetheless. The purpose of this study is to report a case of foreign body reaction (FBR) against a DIAM. A 72-year-old female patient presented with lower back pain and both legs radiating pain. She had undergone DIAM implantation at L4-5 for spinal stenosis 5 years previously. The intervertebral disc space of L4-5, where the DIAM was inserted, had collapsed and degenerative scoliosis had developed due to left-side collapse. MRI showed L3-4 thecal sac compression and left L4-5 foraminal stenosis. The patient underwent removal of the DIAM and instrumented fusion from L3 to L5. During surgery, fluid and granulation tissue were evident around the DIAM. Histopathology showed scattered wear debris from the DIAM causing chronic inflammation due to the resulting FBR. A FBR due to wear debris of a DIAM can induce a hypersensitivity reaction and bone resorption around the implant, causing it to loosen.

• Journal of Sasang Constitutional Medicine
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• v.19 no.2
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• pp.11-21
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• 2007

1. Objectives The object of this thesis is to find the basis on why Jejo was assigned as a Taeumin medicine, and to understand Taeumin edema. 2. Methods ${\ulcorner}$Dongyisusebowon${\lrcorner}$ 'Shinchukbon', 'Gabobon', 'Chobonkwun', other related Sasang Constitutional Medicine(SCM) books, herbal medicine books such as ${\ulcorner}$Bonchokangmok${\lrcorner}$, and etc. were compared and researched. 3. Results & Conclusions (1) In Sasang Constitutional Medicine, edema is seen as a critical condition. The first cause of edema in Taeumin is fatigue, a condition where the flow of Qi and Fluid Qi is stagnated. Secondly, edema is caused as Taeeumin is mentally stressed(勞心焦思) and he/she is unable to accomplish his/her plans over many trials or as when they find pleasure in striving for greed. When Lungs which is Incline & Small Viscera(偏小之臟) in Taeumin decreases, it diminishes Real Count of Longevity(命脈實數) which leads to edema formation. (2) Perspective of Human Nature & Character(心性學) and Regimen(養生法) became included gradually in the treatment methods and prescription of edema in Taeumin as ${\ulcorner}$Dongyisusebowon${\lrcorner}$ was revised over time. The revisions also lead to more diversity in prescriptions. (3) Jejo didn't appear In ${\ulcorner}$Dongyisusebowon${\lrcorner}$ 'Chobonkwun' and 'Gabobon'. It was first presented in 'Shinchukbon' as a medicine to treat edema in Taeumin. (4) Jejo have effects of easing clumps. Also it has a strong radiating ability(發散力) which induces perspiration to treat diseases. Finally Jejo is used to remove Takki(濁氣) by utilizing powerful Exhale Gathering Qi contained in it.

• The Journal of the Acoustical Society of Korea
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• v.33 no.6
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• pp.351-357
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• 2014

In this paper, flow noise characteristics of the hybrid vertical-axis wind turbine is investigated. Hybrid vertical-axis wind turbines consisting of two types of vertical-axis wind turbines, Savonius and Darrieus, are devised to maximize merits of one turbine and thus minimize demerits of the other turbine. In order to predict flow noise radiating from hybrid vertical-axis wind turbines, hybrid computatioinal aero acoustic techniques are used. First, unsteady flow fields around the turbine are predicted using computational fluid dynamics method. Then, the flow noise radiations from the turbines are predicted by applying acoustic analogy to the predicted flow fields. Based on numerical results, noise characteristics of a hybrid vertical-axis wind turbine is investigated and is compared with those of Savonius and Darrieus wind turbines.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.4
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• pp.114-131
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• 1992

In the present work, a two-dimensional boundary-value problem for a large amplitude motion is treated as an initial-value problem by satisfying the exact body-boundary and nonlinear free-surface boundary conditions. The present nonlinear numerical scheme is similar to that described by Vinje and Brevig(1981) who utilized the Cauchy's theorem and assumed the periodicity in the horizontal coordinate. In the present thesis, however, the periodicity in the horizontal coordinate is not assumed. Thus the present method can treat more realistic problems, which allow radiating waves to infinities. In the present method of solution, the original infinite fluid domain, is divided into two subdomains ; ie the inner and outer subdomains which are a local nonlinear subdomain and the truncated infinite linear subdomain, respectively. By imposing an appropriate matching condition, the computation is carried out only in the inner domain which includes the body. Here we adopt the nonlinear scheme of Vinje & Brevig only in the inner domain and respresent the solution in the truncated infinite subdomains by distributing the time-dependent Green function on the matching boundaries. The matching condition is that the velocity potential and stream function are required to be continuous across the matching boundary. In the computations we used, if necessary, a regriding algorithm on the free surface which could give converged stable solutions successfully even for the breaking waves. In harmonic oscillation problem, each harmonic component and time-mean force are obtained by the Fourier transform of the computed forces in the time domain. The numerical calculations are made for the following problems. $\cdot$ Forced harmonic large-amplitude oscillation(${\omega}{\neq}0,\;U=0$) $\cdot$ Translation with a uniform speed(${\omega}=0,\;U{\neq}0$) The computed results are compared with available experimental data and other analytical results.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.278-286
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• 2021

In this study, based on the Computational Fluid Dynamics (CFD) simulation model developed through previous study, inner environmenct of the modified glass greenhouse was predicted. Also, suggested the optimal shape of the greenhouse and location of the heat exchangers for heat energy management of the greenhouse using the developed model. For efficient heating energy management, the glass greenhouse was modified by changing the cross-section design and the location of the heat exchanger. The optimal cross-section design was selected based on the cross-section design standard of Republic of Korea's glass greenhouse, and the Fan Coil Unit(FCU) and the radiating pipe were re-positioned based on "Standard of greenhouse environment design" to enhance energy saving efficiency. The simulation analysis was performed to predict the inner temperature distribution and heat transfer with the modified greenhouse structure using the developed inner environment prediction model. As a result of simulation, the mean temperature and uniformity of the modified greenhouse were 0.65℃, 0.75%p higher than those of the control greenhouse, respectively. Also, the maximum deviation decreased by an average of 0.25℃. And the mean age of air was 18 sec. lower than that of the control greenhouse. It was confirmed that efficient heating energy management was possible in the modified greenhouse, when considered the temperature uniformity and the ventilation performance.