• Proceedings of the KOSOMBE Conference
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• v.1990 no.11
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• pp.5-10
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• 1990

The object detection capabilities of ultrasonic imaging systems are limited by the ability of the detection process to distinguish the resolved object signals from backscattered speckle noise. It has been shown that the phase component of the Fourier transform of the speckle noise is random. Based on this property. we propose a new algorithm for distinguishing between speckle and specular targets. The proposed algorithm is implemented by taking the Fourier transform of the received signal, low-pass filtering the phase, and taking the inverse Fourier transform of the filtered phase to enhance specular reflectors and reduce speckle in the image. Simulations and experiments using phantoms confirm the algorithm yielding significant reduction of speckle noise.

• The Korean Journal of Ceramics
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• v.5 no.3
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• pp.265-269
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• 1999

Polyethylene was modified with silanol groups on its surface by photografting of vinyltrimethoxysilane in vapor phase by using benzophenon as a polymerization initiator and by hydrolyzing the methoxysilane groups into the silanol groups with HCI solution. The modified polyethylene formed a dense and homogeneous apatite layer on its surface in a solution with ion concentrations 1.5 times those of human blood plasma within 21 days. This kind of biomimetic process could provide techniques for fabricating apatite-polymer composites with three dimensional structure analogous to the natural bone.

• Journal of the Korea Computer Graphics Society
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• v.10 no.4
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• pp.1-5
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• 2004

본 논문에서는 인체의 머리 부분을 촬영한 자기 공명 촬영 영상(MRI: Magnetic Resonance Imaging)에서 뇌 영역의 대뇌 피질 만을 분할하는 방법에 대해 제시하고자 한다. 뇌의 해부학적 구조를 파악할 경우에 영상 내에 함께 보여지는 두개골과 뇌척수액 등을 제외한 대뇌피질 영역을 분할하면 보다 효과적인 정보 분석 및 진단이 가능하게 된다. 본 논문에서는 3단계 알고리즘을 제시한다. 첫번째 단계에서는 Speckle reducing anisotropic diffusion (SRAD)를 이용하여 영상 내에 존재하는 잡음을 제거하기 위한 필터링이다. 두번째 단계에서는 필터링된 결과를 이용하여 추출된 임계값과 사용자의 인터렉션인 씨드 포인트를 통해 영상분할을 수행하고, 세 번째 단계에서는 후 처리를 통해 분할 결과를 보완한다. 영상분할 결과의 정확성을 측정하기 위하여 현재 병원의 의료진들이 사용하고 있는 Mayo clinic사의 Analyze를 이용하여 분할된 결과와의 오류를 측정하였다. 또한 최종 결과에 대해 ultravis를 이용한 볼륨 렌더링으로 영상분할의 최종 결과를 제시하였다.

• Speech Sciences
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• v.3
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• pp.38-49
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• 1998

Dysarthrias are a sort of neuromotor disorders because of the weakness of neuromotor controls. They are classified in six types on the basis of Mayo clinic research: flaccid, spastic, ataxic, hypokinetic, hypekinetic and mixed types. Five dysarthria types are investigated in this study. MRI, EMG, neuropathological tests are essential diagnostic processing. Visi-Pitch and Spectrgraphy, CSL are used for assessing dysarthria speech. Maximum phonation time, diadochokinetic rate, Voice Onset Time and substitution rate are the speech evaluation parameters. Maximum phonation time and diadochokinetic rates are the lowest in case of spastic and ataxic dysarthrias. Spastic dysarthria shows the substituted glottalized consonants. However, flaccid, ataxic and hypokinetic dysarthrias show the substituted aspirated consonants. VOT is the longest for hypokinetic dysarthria and the shortest for ataxic dysarthria. Jitter shows higher percentage in comparison with control group. Speech evaluation using experimental phonetic instruments help create on international standardization of speech evaluation for speech disorders.

• Progress in Superconductivity
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• v.8 no.1
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• pp.1-7
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• 2006

We have developed magnetocardiography(MCG) and impedance magnetocardiography(I-MCG) for detecting heart disease by using dc-SQUID technology. The MCG system, using low-Tc SQUID, is being applied commercially for diagnosing heart disease. Using the low-Tc MCG system, many clinical studies on detection of abnormality have been performed. Furthermore, we have developed a portable MCG system using high-Tc SQUID. For detecting changes in kinetic impedance in the heart, an I-MCG system has been demonstrated. The I-MCG system could detect the mechanical movement of the heart. In this report, we review current clinical applications of magnetocardiography and impedance magnetocardiography.

• Journal of the Korean Statistical Society
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• v.29 no.2
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• pp.201-217
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• 2000

The method of generalized estimating equations (GEE) has become very popular for the analysis of longitudinal data. We extend this work to the use of M-estimators; the resultant regression estimates are robust to heavy tailed errors and to outliers. The proposed method does not require correct specification of the dependence structure between observation, and allows for heterogeneity of the error. However, an estimate of the dependence structure may be incorporated, and if it is correct this guarantees a higher efficiency for the regression estimators. A goodness-of-fit test for checking the adequacy of the assumed M-estimation regression model is also provided. Simulation studies are conducted to show the finite-sample performance of the new methods. The proposed methods are applied to a real-life data set.

• Advances in biomechanics and applications
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• v.1 no.2
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• pp.77-83
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• 2014

Creep phenomenon at the scale of bone tissue (small specimens) is known to be present and demonstrated for low strains. Here creep is demonstrated on a pair of fresh-frozen human femurs at the organ level at high strains. Under a constant displacement applied on femur's head, surface strains at the upper neck location increase with time until fracture, that occurs within 7-13 seconds. The monotonic increase in strains provides evidence on damage accumulation in the interior (probably damage to the trabeculae) prior to final fracture, a fact that hints on probable damage of the trabecular bone that occurs prior to the catastrophic fracture of the cortical surface layer.

• Journal of Gynecologic Oncology
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• v.29 no.6
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• pp.94.1-94.10
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• 2018

Endometrial cancer (EC) represents the most common gynecological neoplasm in developed countries. Surgery is the mainstay of treatment for EC. Although EC is characterized by a high prevalence several features regarding its management are still unclear. In particular the execution of lymphadenectomy is controversial. The recent introduction of sentinel node mapping represents the mid-way between the execution and omission of node dissection in EC patients. In the present review we discuss the emerging role of sentinel node mapping in EC. In addition, we discussed how type of tracers utilized and site of injection impacted on sentinel node detection rates. Future perspective regarding EC management are also discussed.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.3
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• pp.227-240
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• 2023

Hilar cholangiocarcinomas are highly aggressive malignancies. They are usually at an advanced stage at initial presentation. Surgical resection with negative margins is the standard of management. It provides the only chance of cure. Liver transplantation has increased the number of 'curative' procedures for cases previously considered to be unresectable. Meticulous and thorough preoperative planning is required to prevent fatal post-operative complications. Extended resection procedures, including hepatic trisectionectomy for Bismuth type IV tumors, hepatopancreaticoduodenectomy for tumors with extensive longitudinal spread, and combined vascular resection with reconstruction for tumors involving hepatic vascular structures, are challenging procedures with surgical indications expanded. Liver transplantation after the standardization of a neoadjuvant protocol described by the Mayo Clinic has increased the number of patients who can undergo operation.

• Archives of Reconstructive Microsurgery
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• v.20 no.1
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• pp.43-50
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• 2011

Lunate revascularization with the vascularized bone grafts is a current concept in the treatment of Kienbo${\ddot{o}}$ck disease. The aim of this study is to present our experience and preliminary results of the treatment using the fourth extensor compartment artery (4 ECA) vascularized bone graft for Kienbo${\ddot{o}}$ck disease. Between May 2009 and June 2010, five patients (3 men and 2 women) with Kienbo${\ddot{o}}$ck disease were treated with 4 ECA vascularized bone grafts. The mean age was 32.8 years and mean follow-up time was 13 months. The patients were composed of two patients in stage II and three patients in stage IIIa according to Lichtman's classification. Modified Mayo wrist score including pain, grip strength, range of motion and functional status and radiographic parameters such as carpal height ratio and radioscaphoid angle were evaluated at a final follow-up. Pain was markedly diminished and modified Mayo wrist score was 82 at last follow up period. There were no or little changes in carpal height ratio and radioscaphoid angle. All patients showed satisfactory bony union and no further lunate collapse on follow-up radiographs. The 4 ECA vascularized bone graft is a reliable alternative procedures among revascularization procedures for treatment of Kienbo${\ddot{o}}$ck's disease. It is less invasive and has low risk of kinking of pedicle compared to the 4+5 ECA vascularized bone graft. However, long term follow-up and MRI evaluation at follow up period should be needed for the future.